Big person to get screwed up, we hear? (5)
I believe the answer is:
titan
'big person' is the definition.
'to get screwed up we hear?' is the wordplay.
'to get screwed up' becomes 'tighten'.
'we hear?' shows a homophone (sound like).
'tighten' sounds like 'TITAN'.
(Other definitions for titan that I've seen before include "Hyperion, for example" , "One of the first pantheon of Greek deities" , "Huge character" , "one of great importance" , "Taint in a great man" .)