Second, trendy sailer (4)
I believe the answer is:
ship
'sailer' is the definition.
(I've seen this in another clue)
'second trendy' is the wordplay.
'second' becomes 's' (common abbreviation).
'trendy' becomes 'hip' (I've seen this in another clue).
's'+'hip'='SHIP'
(Other definitions for ship that I've seen before include "Transport as on sea-going vessel" , "Seagoing boat" , "In a word, final indication of rank or position" , "See 18" , "Ocean vessel" .)