Ricko,
I modified the code as shown so i could simply /define [WORD]
and it works so I'm suspecting you have other issues or are trying to
trigger your own 'on text' event which is impossible.

on *:sockopen:ud*:{ 
  tokenize 32 $sock($sockname).mark 
  if ($sockerr) { $5-6 Socket error! | return }
  $2-4 GET $+(/iphone/search/define?term=,$1) HTTP/1.1
  $2-4 Host: $+($sock($sockname).addr,$str($crlf,2)) 
  $2-4 Connection: close
}
on *:sockread:ud*:{
  tokenize 32 $sock($sockname).mark
  if ($sockerr) { $5-6 Socket error! | return } | var %ud | sockread %ud
  if (undefined isin %ud) { $5-6 $qt($replace($1,+,$chr(32))) is $+($v1,!) }
  elseif ($regex(%ud,/"definition":"(.*)/)) { $5-6 $remde($gettok($regml(1),1,34)) }
}
alias define {
  set -l %ud $+(ud,$str($ticks,3))
  $+(sock,$iif($sock(%ud),close,open) %ud www.urbandictionary.com 80)
  sockmark %ud $replace($strip($1-),$chr(32),+) sockwrite -nt %ud .echo -a 
}
alias remde var %. | noop $regsub($1,/\134r\134n/g,$chr(32),%.) | return %.