Sleep in intermittently and secure free time (7)
I believe the answer is:
leisure
'free time' is the definition.
(I've seen this before)
'sleep in intermittently and secure' is the wordplay.
'intermittently' means one should take alternating letters.
'and' is a charade indicator (letters next to each other).
'secure' becomes 'sure' (both can mean certain or stable).
'sleep'+'in'='sleepin'
The alternate letters of 'sleepin' are 'lei'.
'lei'+'sure'='LEISURE'
(Other definitions for leisure that I've seen before include "Free time as for resting or play" , "Rest, relaxation" , "casual wear" , "time-off" , "Free time, comfort and convenience" .)