Fashionable to taste one drink primarily bland (7)
I believe the answer is:
insipid
'bland' is the definition.
(synonyms)
'fashionable to taste one drink primarily' is the wordplay.
'fashionable' becomes 'in' (similar in meaning).
'to taste' becomes 'sip' (I've seen this in another clue).
'one' becomes 'i' (Roman numeral).
'primarily' suggests taking the first letters.
The initial letter of 'drink' is 'd'.
'in'+'sip'+'i'+'d'='INSIPID'
(Other definitions for insipid that I've seen before include "Lacking 10" , "without taste" , "Lacking in flavour or interest" , "dry" , "Colourless" .)