Note that the answers above rely on the array being comprised of single words (which may well be the case), However, if the elements being searched contain multi-word phrases or (for example) sentences (which is not specified in the OP), the results may not be as illustrated.

#! /usr/bin/perl
use strict;
use warnings;

my @other_stuff = ("run", "running", "runs", "runt", "I run a mile per
+ day.", "Run, rabbit, run!", "One mile per day is easily runnable");

for my $element(@other_stuff) { print $element ."\n"; }

print "-" x20 . "\n";

my @stuff = grep /\brun\b/x, @other_stuff;

for (@stuff) { print $_ . "\n"; }
[download]

produces...

ww@GIG:~/pl_test$ perl greprun.pl
run
running
runs
runt
I run a mile per day.
Run, rabbit, run!
One mile per day is easily runnable
--------------------
run
I run a mile per day.
Run, rabbit, run!
ww@GIG:~/pl_test$
[download]

Precise specification of a problem-area makes it easier for Perl Monks to provide proper answers (and standard spelling is a "good thing," too).