Good man restraining gee-gee that's dazed (6)
I believe the answer is:
groggy
'dazed' is the definition.
('groggy' can be a synonym of 'dazed')
'good man restraining gee-gee' is the wordplay.
'good' becomes 'g' (abbreviation).
'man' becomes 'roy' (I've seen this before**).
'restraining' means one lot of letters goes inside another.
'gee' becomes 'g' ('g' can be a synonym of 'gee').
'gee' becomes 'g' ('g' can be a synonym of 'gee').
'g'+'g'='gg'
'roy' going around 'gg' is 'roggy'.
'g'+'roggy'='GROGGY'
'that's' acts as a link.
(Other definitions for groggy that I've seen before include "In a daze" , "Confused and slow to react" , "Dizzy and unsteady on the feet" , "Dizzy, slow on the feet" , "spaced out" .)