(In way of thanks to loge @ 27)
And now ladies and gentlemen, for your entertainment and delight, let me present for you my own fantastical parsing of 23. A parsing of coruscating complexity that is bound to astonish and impress.
(This is after guessing the answer from the def and crossers – and realising the first two letters were missing from the wordplay.)
TC = first letters of ‘too crude’.
A = ‘assumed’.
ST = abbr of standard.
S = son (i.e. ‘issue.)
Which just goes to demonstrate how easy it is - for me, anyway -to disappear up one’s own fundament.