Seaman interrupts hit at home (7)
I believe the answer is:
habitat
'home' is the definition.
(I've seen this before)
'seaman interrupts hit at' is the wordplay.
'seaman' becomes 'ab' (short for able seaman).
'interrupts' is an insertion indicator.
'ab' put within 'hit' is 'habit'.
'habit'+'at'='HABITAT'
(Other definitions for habitat that I've seen before include "Natural environment (of creature)" , "(Organism's) natural home" , "Local environment" , "Animal's natural home" , "One's normal environment" .)