State could be green about Monday (7)
I believe the answer is:
vermont
'state' is the definition.
(Vermont is an example)
'green about monday' is the wordplay.
'green' becomes 'vert' (I've seen this before).
'about' means one lot of letters goes inside another.
'monday' becomes 'Mon' (short for Monday).
'vert' placed around 'mon' is 'VERMONT'.
'could be' acts as a link.
(Other definitions for vermont that I've seen before include "New England state, capital Montpelier" , "The Green Mountain state" , "US state, named for the Green Mountains" .)