Board and lodging (4)
I believe the answer is:
keep
'board and lodging' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for keep that I've seen before include "Main tower within the walls of a castle" , "Only one cricketer on field will" , "Retain; part of castle" , "Observe - reserve - preserve" , "Act as custodian of" .)