The most common and most likely answer to this crossword clue is the 6 letter word PILOSE
I've seen this crossword clue in The Guardian
P
I
L
O
S
E
More clues leading to the result PILOSE
Buddy explains!
The straight part
We know that "with plenty of 21" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case with plenty of 21 = pilose.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PILOSE mean?
PILOSE adjective- Covered with fine hair.