Require this at the end of the day, being insecure (5)
I believe the answer is:
needy
'insecure' is the definition.
(I've seen this in another clue)
'require this at the end of the day' is the wordplay.
'require' becomes 'need' (synonyms).
'this at the end of' indicates one should take the final letters.
The last letter of 'day' is 'y'.
'need'+'y'='NEEDY'
'being' acts as a link.
(Other definitions for needy that I've seen before include "Poor; indigent" , "Craving attention" , "Disadvantaged" , "Wanting attention" , "lacking resources" .)