… put a whiskey into another drink to catch a boy (6)
I believe the answer is:
gawain
'a boy' is the definition.
(boy's name)
'put a whiskey into another drink' is the wordplay.
'put' means one lot of letters goes inside another.
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'into' means one lot of letters goes inside another.
'another drink' becomes 'gain' (I can't explain this - if you can you should give a lot more credence to this answer).
'w' going within 'gain' is 'gawin'.
'a' put into 'gawin' is 'GAWAIN'.
'to catch' acts as a link.
(Other definitions for gawain that I've seen before include "One of King Arthur's knights" , "Arthurian knight of the Round Table" , "Man at round table" , "K" , "round a table for him and his comrades?" .)