Promise the return of some imprisoned rowdies (4)
I believe the answer is:
word
'promise' is the definition.
(as in 'I give you my word')
'return of some imprisoned rowdies' is the wordplay.
'return of' shows that the letters should be reversed in order.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'drow' is hidden within 'imprisoned rowdies'.
'drow' reversed gives 'WORD'.
'the' is the link.
(Other definitions for word that I've seen before include "Puzzle with solutions reading the same down as across" , "Promise; news" , "usually comes with more than one letter" , "Element of language" , "Term" .)