Joe's in the pub, as is reasonable (7)
I believe the answer is:
logical
'is reasonable' is the definition.
(similar in meaning)
'joe's in the pub' is the wordplay.
'joe' becomes 'GI' (GI Joe).
'in the' is an insertion indicator.
'pub' becomes 'local' (one's local pub).
'gi' going into 'local' is 'LOGICAL'.
'as' is the link.
(Other definitions for logical that I've seen before include "Objective" , "Showing rational thought" , "Well-reasoned" , "entirely reasonable" , "Consistent with reason" .)