Dine out and stop being vague (13)
I believe the answer is:
indeterminate
'vague' is the definition.
(I've seen this before)
'dine out and stop' is the wordplay.
'dine out' becomes 'inde' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' says to put letters next to each other.
'stop' becomes 'terminate' (synonyms).
'inde'+'terminate'='INDETERMINATE'
'being' acts as a link.
Can you help me to learn more?
(Other definitions for indeterminate that I've seen before include "Unspecified" , "Not exactly defined" , "uncertain result?" , "Inconclusive" , "Not precisely fixed" .)