diff --git a/R/function_checkers.R b/R/function_checkers.R
index faec6e2..0eb87ba 100644
--- a/R/function_checkers.R
+++ b/R/function_checkers.R
@@ -14,18 +14,18 @@
 #' input returns a numeric vector output of the same length as the input, with
 #' finite non-missing values \eqn{\geq} 0.0.
 #'
-#' @param fn A function. This is expected to be a function evaluating the
+#' @param func A function. This is expected to be a function evaluating the
 #' density of a distribution at numeric values.
 #' @param n_req_args The number of required arguments, i.e., arguments without
 #' default values.
-#' @param n The number of elements over which to evaluate the function `fn`.
-#' Defaults to 10, and `fn` is evaluated over `seq(n)`.
+#' @param n The number of elements over which to evaluate the function `func`.
+#' Defaults to 10, and `func` is evaluated over `seq(n)`.
 #'
-#' @return A logical for whether the function `fn` fulfils conditions specified
-#' in the respective checks.
+#' @return A logical for whether the function `func` fulfils conditions
+#' specified in the respective checks.
 #' @keywords internal
-test_fn_req_args <- function(fn, n_req_args = 1) {
-  # NOTE: replacing checkmate::assert_count()
+test_func_req_args <- function(func, n_req_args = 1) {
+  # check for a non-negative integerish value
   stopifnot(
     "`n_req_args` must be a single number" = (is.numeric(n_req_args)) &&
       (length(n_req_args) == 1),
@@ -34,31 +34,31 @@ test_fn_req_args <- function(fn, n_req_args = 1) {
     "`n_req_args` must be a natural number > 0" = (n_req_args > 0) &&
       (n_req_args %% 1 == 0)
   )
-  # NOTE: using formals(args(fn)) to allow checking args of builtin primitives
-  # for which formals(fn) would return NULL and cause the check to error
+  # NOTE: using formals(args(func)) to allow checking args of builtin primitives
+  # for which formals(func) would return NULL and cause the check to error
   # NOTE: errors non-informatively for specials such as `if`
-  is.function(fn) &&
+  is.function(func) &&
     Reduce(
       x = Map(
         function(x, y) {
           is.name(x) && y != "..."
         },
-        formals(args(fn)), names(formals(args(fn)))
+        formals(args(func)), names(formals(args(func)))
       ),
       f = `+`
     ) == n_req_args
 }
 
 #' @name function_checkers
-test_fn_num_out <- function(fn, n = 10) {
-  # NOTE: replacing checkmate::assert_count()
+test_func_num_out <- function(func, n = 10) {
+  # check for a non-negative integerish value
   stopifnot(
     "`n` must be a single number" = (is.numeric(n)) && (length(n) == 1),
     "`n` must be finite and non-missing" = (is.finite(n)) && (!is.na(n)),
     "`n` must be a natural number > 0" = (n > 0) && (n %% 1 == 0),
-    "`fn` must be a function" = is.function(fn)
+    "`func` must be a function" = is.function(func)
   )
-  out <- fn(seq(n))
+  out <- func(seq(n))
 
   # return logical output of conditions
   is.numeric(out) && (length(out) == n) && (!anyNA(out)) &&
diff --git a/man/function_checkers.Rd b/man/function_checkers.Rd
index f499ca7..45362e6 100644
--- a/man/function_checkers.Rd
+++ b/man/function_checkers.Rd
@@ -2,27 +2,27 @@
 % Please edit documentation in R/function_checkers.R
 \name{function_checkers}
 \alias{function_checkers}
-\alias{test_fn_req_args}
-\alias{test_fn_num_out}
+\alias{test_func_req_args}
+\alias{test_func_num_out}
 \title{Check functions passed to exported functions}
 \usage{
-test_fn_req_args(fn, n_req_args = 1)
+test_func_req_args(func, n_req_args = 1)
 
-test_fn_num_out(fn, n = 10)
+test_func_num_out(func, n = 10)
 }
 \arguments{
-\item{fn}{A function. This is expected to be a function evaluating the
+\item{func}{A function. This is expected to be a function evaluating the
 density of a distribution at numeric values.}
 
 \item{n_req_args}{The number of required arguments, i.e., arguments without
 default values.}
 
-\item{n}{The number of elements over which to evaluate the function \code{fn}.
-Defaults to 10, and \code{fn} is evaluated over \code{seq(n)}.}
+\item{n}{The number of elements over which to evaluate the function \code{func}.
+Defaults to 10, and \code{func} is evaluated over \code{seq(n)}.}
 }
 \value{
-A logical for whether the function \code{fn} fulfils conditions specified
-in the respective checks.
+A logical for whether the function \code{func} fulfils conditions
+specified in the respective checks.
 }
 \description{
 Internal helper function that check whether a function passed as
diff --git a/tests/testthat/test-function_checkers.R b/tests/testthat/test-function_checkers.R
index aaa8641..2e03371 100644
--- a/tests/testthat/test-function_checkers.R
+++ b/tests/testthat/test-function_checkers.R
@@ -1,60 +1,60 @@
-#### Checks on test_fn_req_args() ####
+#### Checks on test_func_req_args() ####
 test_that("Function to check N required arguments", {
   # Test function to check number of required arguments
   expect_true(
-    test_fn_req_args(
+    test_func_req_args(
       function(x) dgamma(x, 5, 1)
     )
   )
   # `+` needs two arguments
   expect_true(
-    test_fn_req_args(
+    test_func_req_args(
       `+`, 2L
     )
   )
   expect_false(
-    test_fn_req_args(
+    test_func_req_args(
       `+`, 1L
     )
   )
   expect_false(
-    test_fn_req_args(
+    test_func_req_args(
       function(x, y, ...) dgamma(x, 5, 1, ...) + y
     )
   )
   expect_true(
-    test_fn_req_args(
+    test_func_req_args(
       dgamma, 2
     )
   )
 
   # fails on poorly specified n
   expect_error(
-    test_fn_req_args("dummy_fn", seq(10)),
+    test_func_req_args("dummy_fn", seq(10)),
     regexp = "`n_req_args` must be a single number"
   )
   expect_error(
-    test_fn_req_args("dummy_fn", -1),
+    test_func_req_args("dummy_fn", -1),
     regexp = "`n_req_args` must be a natural number > 0"
   )
   expect_error(
-    test_fn_req_args("dummy_fn", NA_real_),
+    test_func_req_args("dummy_fn", NA_real_),
     regexp = "`n_req_args` must be finite and non-missing"
   )
   expect_error(
-    test_fn_req_args("dummy_fn", Inf),
+    test_func_req_args("dummy_fn", Inf),
     regexp = "`n_req_args` must be finite and non-missing"
   )
 
   # expect TRUE when an appropriate primitive is passed
   # NOTE: Passes as this primitive has one arg
   expect_true(
-    test_fn_req_args(is.list)
+    test_func_req_args(is.list)
   )
 
   ## functions with ellipsis
   expect_true(
-    test_fn_req_args(
+    test_func_req_args(
       function(x, ...) dgamma(x, 5, 1, ...)
     )
   )
@@ -64,35 +64,35 @@ test_that("Function to check N required arguments", {
 test_that("Function to check numeric output", {
   # well specified case
   expect_true(
-    test_fn_num_out(
+    test_func_num_out(
       function(x) dgamma(x, 5, 1)
     )
   )
   # false on wrong input type
   expect_error(
-    test_fn_num_out("dummy_fn"),
-    regexp = "`fn` must be a function"
+    test_func_num_out("dummy_fn"),
+    regexp = "`func` must be a function"
   )
   # fails on poorly specified n
   expect_error(
-    test_fn_num_out("dummy_fn", seq(10)),
+    test_func_num_out("dummy_fn", seq(10)),
     regexp = "`n` must be a single number"
   )
   expect_error(
-    test_fn_num_out("dummy_fn", -1),
+    test_func_num_out("dummy_fn", -1),
     regexp = "`n` must be a natural number > 0"
   )
   expect_error(
-    test_fn_num_out("dummy_fn", NA_real_),
+    test_func_num_out("dummy_fn", NA_real_),
     regexp = "`n` must be finite and non-missing"
   )
   expect_error(
-    test_fn_num_out("dummy_fn", Inf),
+    test_func_num_out("dummy_fn", Inf),
     regexp = "`n` must be finite and non-missing"
   )
   # false on wrong return type
   expect_false(
-    test_fn_num_out(
+    test_func_num_out(
       function(x, ...) as.character(dgamma(x, 5, 1, ...))
     )
   )
@@ -102,6 +102,6 @@ test_that("Function to check numeric output", {
     a[-1]
   }
   expect_false(
-    test_fn_num_out(fn)
+    test_func_num_out(fn)
   )
 })