I want to illustrate an iterative solution that uses map and grep. Admittedly this method puts a loop inside of a loop (rather than just one loop). Here goes.....

my @lines = qw/marge homer bart jerry maggie george elaine
               kramer lisaross chandler fibi joey monica
               rachel batman robin catwoman batgirl
               superman thetick hollywood studio universal
               compton harbor downtown monica venice oc
               oxnard ventura oaks/;

my @kwords = qw/bart maggie monica pete/;
my @matches = map { my $kword=$_; grep /\b$kword\b/, @lines } @kwords;
{
    local $, = "\t";
    print @matches;
}
[download]

This is just an example. A little tinkering will match it to your needs. Enjoy!

Update: I tested the above method against the regexp method in the first followup in this thread. The regexp (alternation) method proved to be faster for this small test-set of data. Even when I grew the keyword list to about 40 words, and the array of strings to find keywords in to about 40 lines of 10 "words" each, I still found alternation to be faster. I don't know what to expect if the keyword list gets REALLY big. Obviously my method puts a loop inside a loop. But alternation itself isn't considered terribly fast. Someone with a lot of test data might be able to shed light.