Cold and inexperienced, Heather is moving slowly (8)
I believe the answer is:
crawling
'is moving slowly' is the definition.
(I've seen this before)
'cold and inexperienced heather' is the wordplay.
'cold' becomes 'c' (eg on taps).
'and' means one lot of letters go next to another.
'inexperienced' becomes 'raw' ('raw' can be similar in meaning to 'inexperienced').
'heather' becomes 'ling' ('ling' can be a synonym of 'heather').
'c'+'raw'+'ling'='CRAWLING'
(Other definitions for crawling that I've seen before include "Behaving obsequiously" , "Creeping slowly along the ground" , "Creeping or grovelling" , "Moving on hands and knees" , "Toadying" .)