Implied the Arctic Circle is turning heads (5)
I believe the answer is:
tacit
'implied' is the definition.
(synonyms)
'the arctic circle is turning heads' is the wordplay.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'heads' indicates taking the first letters.
The initial letters of 'arctic circle is turning' is 'acit'.
't'+'acit'='TACIT'
(Other definitions for tacit that I've seen before include "Understood, implicit" , "Silently understood" , "without speaking" , "Unrecorded" , "Understood without being directly expressed" .)