Engineer is cornered? Think again (10)
I believe the answer is:
reconsider
'think again' is the definition.
('consider' is an answer for 'think' so perhaps 'reconsider' is OK for 'think again')
'engineer is cornered?' is the wordplay.
'engineer' is an anagram indicator.
'is'+'cornered'='iscornered'
'iscornered' is an anagram of 'RECONSIDER'.
(Other definitions for reconsider that I've seen before include "Think again" , "Have second thoughts" , "Nice orders ( anag.)" , "Ponder further" .)