First time out, useless opener dismissed — a liability? (4)
I believe the answer is:
'a liability?' is the definition.
(debt is a kind of liability)
'first time' is the wordplay.
'first' becomes 'deb' (I am not sure about this - if you are sure you should believe this answer much more).
'time' becomes 't'.
'out useless opener dismissed' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
(Other definitions for debt that I've seen before include "Sum of money that's owed" , "Financial problem?" , "What's due" , "sense of gratitude" , "state of obligation" .)