Parts of sentence served by her pass turbulently (7)
I believe the answer is:
phrases
'parts of sentence' is the definition.
(groups of words)
'by her pass turbulently' is the wordplay.
'by' means one lot of letters go next to another.
'turbulently' indicates an anagram.
'her' next to 'pass' is 'herpass'.
'herpass' is an anagram of 'PHRASES'.
'served' is the link.
(Other definitions for phrases that I've seen before include "Parts of sentances without verbs" , "Parts of sentences without verbs" , "A group of words standing together" , "Meaningful groups of words" , "Grammatical constituents without finite verbs" .)