Husband leaving shore working in lighthouse (6)
I believe the answer is:
beacon
'lighthouse' is the definition.
('beacon' can be a synonym of 'lighthouse')
'husband leaving shore working' is the wordplay.
'husband' becomes 'h'.
'leaving' indicates named letters should be taken away.
'shore' becomes 'beach' (I've seen this before).
'working' becomes 'on'.
'beach' with 'h' taken away is 'beac'.
'beac'+'on'='BEACON'
'in' is the link.
(Other definitions for beacon that I've seen before include "Signal fire - signalling buoy" , "Signal light on hill" , "Warning, guiding, fire" , "Directional transmitter" , "Shining light (on top of a hill?)" .)