The first half of this should be considered (7)
I believe the answer is:
thought
'be considered' is the definition.
(I've seen this before)
'the first half of this should' is the wordplay.
'the first half of' suggests halving the letters.
'should' becomes 'ought' (synonyms).
'this' cut in half is 'th'.
'th'+'ought'='THOUGHT'
(Other definitions for thought that I've seen before include "Cogitated" , "Mental idea" , "Reflection" , "Thinking process" , "Supposed" .)