As ever I can't parse some answers and would be grateful for assistance:
7A Skill in abundance (8)
Answer: TRICKERY
What's the relevance of 'abundance' here?
16A Don's idea of a joke (3-2)
Answer: PUT ON
Can't see relevance of 'Don's idea'
21A A scholar's old-fashioned pop
Answer: PATER
I get 'old-fashioned pop' but not how 'A scholar' fits in
6D Nominally high-sounding fellow
Answer: HYMAN
I understand HY = 'high" and MAN = "fellow" but as far as I can see 'HYMAN' isn't a word in the dictionary (as opposed to 'hymen')