In fable, Noah is at sea (11)
I believe the answer is:
fashionable
'in' is the definition.
('fashionable' can be similar in meaning to 'in')
'fable noah is at sea' is the wordplay.
'at sea' is an anagram indicator.
'fable'+'noah'+'is'='fablenoahis'
'fablenoahis' with letters rearranged gives 'FASHIONABLE'.
(Other definitions for fashionable that I've seen before include "What's in" , "A la mode" , "Modish" , "Trendy" .)