... however tempting at first consideration (7)
I believe the answer is:
thought
'consideration' is the definition.
(I've seen this before)
'however tempting at first' is the wordplay.
'however' becomes 'though' (synonyms).
'at first' suggests taking the first letters.
The initial letter of 'tempting' is 't'.
'though'+'t'='THOUGHT'
(Other definitions for thought that I've seen before include "Study" , "Pensee; consideration" , "Musing" , "Mental idea" , "Cogitated" .)