Crab maybe walked about, almost curious (7)
I believe the answer is:
decapod
'crab maybe' is the definition.
'walked about almost curious' is the wordplay.
'walked' becomes 'paced' (pacing is a kind of walking**).
'about' is a reversal indicator.
'almost' means to remove the last letter (most of the word but not all of it).
'curious' becomes 'odd' (I've seen this before).
'paced' back-to-front is 'decap'.
'odd' with its final letter removed is 'od'.
'decap'+'od'='DECAPOD'
(Other definitions for decapod that I've seen before include "Say, crab" , "Crustacean with five pairs of walking limbs" , "lobster, say" , "sea creature" , "Such as shrimp or lobster" .)