Hail the latest fashion as common (7)
I believe the answer is:
average
'common' is the definition.
(I've seen this in another clue)
'hail the latest fashion' is the wordplay.
'hail' becomes 'ave' (I've seen this before).
'the latest fashion' becomes 'rage' (I've seen this in another clue).
'ave'+'rage'='AVERAGE'
'as' is the link.
(Other definitions for average that I've seen before include "Mean - typical" , "Middle value, the norm" , "The statistical norm" , "Normal; mean" , "Mean, median or middling" .)