In net, dry rocks (6)
I believe the answer is:
trendy
'in' is the definition.
(thesaurus)
'net dry rocks' is the wordplay.
'rocks' indicates an anagram.
'net'+'dry'='netdry'
'netdry' anagrammed gives 'TRENDY'.
(Other definitions for trendy that I've seen before include "Smart" , "Up to date, fashionable" , "Up-to-date with the latest fad" , "With it, a la mode" , "Chic (colloq.)" .)