For fear of being in a humble state (4)
I believe the answer is:
lest
'for fear' is the definition.
(I've seen this in other clues)
'being in a humble state' is the wordplay.
'being in' indicates the answer is hidden within the clue.
'LEST' is hidden in the letters of 'humble state'.
'of' acts as a link.
(Other definitions for lest that I've seen before include "For fear that; in order to prevent" , "For fear that (something happens)" , "In case" , "In order not to, to avoid the risk that" , "To avoid the risk that - we forget?" .)