Learner is bad, coming out with impromptu comments (2-4)
I believe the answer is:
ad-libs
'comments' is the definition.
(I know this)
'learner is bad coming out' is the wordplay.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'coming out' indicates an anagram.
'l'+'is'+'bad'='lisbad'
'lisbad' anagrammed gives 'AD-LIBS'.
'with impromptu' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ad-libs that I've seen before include "Extemporary remarks" , "Improvises" , "Extemporaneous remarks" .)