Pretentious cafe fed roughly about twenty at first (8)
I believe the answer is:
affected
'pretentious' is the definition.
(I've seen this before)
'cafe fed roughly about twenty at first' is the wordplay.
'roughly' is an anagram indicator.
'about' indicates putting letters inside.
'at first' indicates taking the first letters.
The first letter of 'twenty' is 't'.
'cafe'+'fed'='cafefed'
'cafefed' with letters rearranged gives 'affeced'.
'affeced' placed around 't' is 'AFFECTED'.
(Other definitions for affected that I've seen before include "Deeply moved" , "Made a difference to" , "Putting on airs, being emotionally moved" , "in a pretentious way" , "Pretentious; changed" .)