A term's misused in a rush (6)
I believe the answer is:
stream
'a rush' is the definition.
(thesaurus)
'a term's misused in' is the wordplay.
'misused' is an anagram indicator.
'in' means one lot of letters goes inside another.
'terms' is an anagram of 'strem'.
'a' placed into 'strem' is 'STREAM'.
(Other definitions for stream that I've seen before include "comprising a load of drips?" , "Small narrow river" , "Brook or small river" , "course" , "selected pupils" .)