Half of them should be considered (7)
I believe the answer is:
thought
'be considered' is the definition.
(I've seen this before)
'half of them should' is the wordplay.
'half of' means to take half the letters.
'should' becomes 'ought' (synonyms).
'them' cut in half is 'th'.
'th'+'ought'='THOUGHT'
(Other definitions for thought that I've seen before include "Reflection" , "Performed brain operations" , "Deliberated" , "Cogitated" , "Cogitation" .)