Held in chains, is tentatively pressing (9)
I believe the answer is:
insistent
'pressing' is the definition.
('insistent' can be a synonym of 'pressing')
'held in chains is tentatively' is the wordplay.
'held in' indicates a hidden word.
'INSISTENT' is hidden in the letters of 'chains is tentatively'.
(Other definitions for insistent that I've seen before include "Refusing to be thwarted" , "Unrelenting" , "Unwilling to take "no" for an answer" , "Compelling attention" , "Determined" .)