Wasted and full of oneself - no use whatever (3,2,4)

I believe the answer is:

all in vain

'no use whatever' is the definition.
(in vain can mean useless)

'wasted and full of oneself' is the wordplay.
'wasted' becomes 'all in' (both can mean tired or exhausted).
'and' says to put letters next to each other.
'full of oneself' becomes 'vain' (full of oneself means vain or arrogant).
'allin'+'vain'='ALL IN VAIN'

Want a hint initially instead of a full solution? Install my app