Many with inadequate rise languish (5)
I believe the answer is:
droop
'languish' is the definition.
(I've seen this before)
'many with inadequate rise' is the wordplay.
'many' becomes 'd'.
'with' says to put letters next to each other.
'inadequate' becomes 'poor' (synonyms).
'rise' is a reversal indicator.
'poor' back-to-front is 'roop'.
'd'+'roop'='DROOP'
(Other definitions for droop that I've seen before include "lose heart" , "be despondent" , "Decline" , "Sag, hang down" , "Sag wearily" .)