Disapproval expressed about a doctor is growing (6)
I believe the answer is:
bamboo
'growing' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'disapproval expressed about a doctor' is the wordplay.
'disapproval expressed' becomes 'boo' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'about' means one lot of letters go next to another.
'a doctor' becomes 'bam' (I've seen this in other clues).
'boo' put after 'bam' is 'BAMBOO'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for bamboo that I've seen before include "Thick tropical cane" , "Tropical cane with hollow centres, used for furniture" , "Tropical grass/wood" , "Panda's dinner?" , "Tall woody plant" .)