Yes, you show no code, the problem description is very vague, you don't say with what the words are to be 'replaced', and yes, this does smell like homework, but...
c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = 'In the table above, the characters themselves, in the first
+column, are links to descriptions of characters';
print qq{'$s'};
;;
my %xlate =
qw(table tooble characters croobles selves others first second
+links loonks);
;;
my ($word) =
map qr{ $_ }xms,
join q{ | },
keys %xlate
;
print $word;
;;
$s =~ s{ ($word) }{$xlate{$1}}xmsg;
print qq{'$s'};
"
'In the table above, the characters themselves, in the first column, a
+re links to descriptions of characters'
(?msx-i: first | selves | table | links | characters )
'In the tooble above, the croobles themothers, in the second column, a
+re loonks to descriptions of croobles'
Update: Caution: long lines: some wraparound may have occurred.
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