Word of disapproval when learner’s penned rubbish (4)
I believe the answer is:
blah
'rubbish' is the definition.
(I've seen this in another clue)
'word of disapproval when learner's penned' is the wordplay.
I cannot really understand how this works, but
'learner' could be 'l' (as in a learner driver with L-plates on their car) and 'l' is located in the answer.
'word of disapproval' could be 'bah' (I've seen this in another clue) and 'bah' is found within the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for blah that I've seen before include "bunkum!" , "Bombast" , "Claptrap" , "Pretentious waffle" , "Meaningless substitute for tedious words" .)