Most scheming to get agreement accepted by special officer (6)
I believe the answer is:
slyest
'most scheming' is the definition.
Both the answer and definition are superlative adjectives. Maybe they are linked in a way I don't understand?
'agreement accepted by special officer' is the wordplay.
'agreement' becomes 'yes' (I've seen this in another clue).
'accepted by' indicates putting letters inside.
'special' becomes 'S' (common abbreviation as in Special Air Service).
'officer' becomes 'lt' (abbreviation for lieutenant).
's'+'lt'='slt'
'yes' put within 'slt' is 'SLYEST'.
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for slyest that I've seen before include "Most cunning" , "most roguish" .)