Feeling one must leave for a time? (8)
I believe the answer is:
sentence
'a time?' is the definition.
('time' can refer to a prison sentence)
'feeling one must leave' is the wordplay.
'feeling' becomes 'sentience' (something sentient is conscious or feeling).
'one' becomes 'i' (Roman numeral).
'must leave' is a deletion indicator.
'sentience' with 'i' taken away is 'SENTENCE'.
'for' is the link.
(Other definitions for sentence that I've seen before include "A word-string - or a legal punishment" , "delivered in a few words" , "Set of words or legal punishment" , "unit booked?" , "life perhaps" .)