Board contracted Mia (4)
I believe the answer is:
plan
'mia' is the definition.
I can't tell whether this definition defines the answer.
'board contracted' is the wordplay.
'board' becomes 'plank' (synonyms).
'contracted' means to remove the last letter (to contract is to shorten).
'plank' with its final letter taken off is 'PLAN'.
Can you help me to learn more?
(Other definitions for plan that I've seen before include "Scheme - map" , "Contrive" , "Diagram; design" , "Schedule" , "Large-scale map" .)