Matches could make you squeal (6)
I believe the answer is:
equals
'matches' is the definition.
('equal' can be a synonym of 'match')
'could make you squeal' is the wordplay.
'could make you' indicates an anagram.
'squeal' with letters rearranged gives 'EQUALS'.
(Other definitions for equals that I've seen before include "sign" , "Persons of the same rank, for instance" , "Is identical or equivalent to" , "Is as good as" , "Peer group" .)