Figure initially crawling past into lair (7)
I believe the answer is:
decagon
'figure' is the definition.
(I've seen this before)
'initially crawling past into lair' is the wordplay.
'initially' indicates taking the first letters.
'past' becomes 'ago' ('ago' can be similar in meaning to 'past'**).
'into' is an insertion indicator.
'lair' becomes 'den' ('den' can be a synonym of 'lair').
The initial letter of 'crawling' is 'c'.
'c'+'ago'='cago'
'cago' put within 'den' is 'DECAGON'.
(Other definitions for decagon that I've seen before include "A polygon -- eg can-do (anag)" , "10-sided figure" , "Go, dance on geometric figure with ten sides" , "Ten-sided shape" , "Figure with 10 sides" .)