21 across
One
of
the
Trumps
hiding
small
toe-curling
secret
(8)
One of the Trumps hiding small toe-curling secret (8)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
The definition is secret, meaning hidden or known only to a few. "One of the Trumps" gives ERIC (one of Donald Trump's children). "Small" abbreviates to S, and "toe-curling" tells us to make an anagram of TOE, giving OTE. Then ERIC "hiding" S + OTE means ERIC contains SOTE inside it: E-(SOTE)-RIC, spelling out ESOTERIC.