But there are limits to how punny you can be, at least under “standard” rules. E.g. “indeed” to clue insertion into DEED (“in deed”) probably isn’t fair
But there is a type of CC called the “cryptic definition” where puns must be used. The classic example is “Flower” for “River”
So “Flower in London? (6)” is THAMES, not an actual species of flower endemic to London