Poets start to drink in pubs (5)
I believe the answer is:
bards
'poets' is the definition.
(bard is a kind of poet)
'start to drink in pubs' is the wordplay.
'start to' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'pubs' becomes 'bars' (I've seen this in another clue).
The first letter of 'drink' is 'd'.
'd' put within 'bars' is 'BARDS'.
(Other definitions for bards that I've seen before include "Welsh poets" , "Celtic minstrels or poets" .)