Tries to take in tailor’s top suit (6)
I believe the answer is:
hearts
'suit' is the definition.
(hearts is a playing card suit)
'tries to take in tailor's top' is the wordplay.
'tries' becomes 'hears' (as in trying or hearing in a trial).
'to take in' is an insertion indicator.
'top' indicates taking the first letters.
The initial letter of 'tailors' is 't'.
'hears' enclosing 't' is 'HEARTS'.
(Other definitions for hearts that I've seen before include "Scots club nickname; suit" , "Playing card suit" , "Scottish footballers" , "Major suit at cards" , "not clubs" .)