Hold onto unworkable relationship, initially for some time (4)
I believe the answer is:
hour
'some time' is the definition.
(hour is a kind of time)
'hold onto unworkable relationship initially' is the wordplay.
'initially' says to take the initial letters.
The initial letters of 'hold onto unworkable relationship' is 'HOUR'.
'for' acts as a link.
(Other definitions for hour that I've seen before include "3,600 seconds" , "See 24" , "See 20" , "Length of time" , "Time within day" .)