Unusual cottage, I think (8)
I believe the answer is:
cogitate
'think' is the definition.
(synonyms)
'unusual cottage i' is the wordplay.
'unusual' indicates anagramming the letters.
'cottage'+'i'='cottagei'
'cottagei' is an anagram of 'COGITATE'.
(Other definitions for cogitate that I've seen before include "Ruminate" , "Deliberate" , "Do some thinking" , "Think, meditate" , "Meditate - reflect" .)