This is a cryptic crossword. Howevr, several of the words require
several letters to be placed in a single square. These letters form a
letter-number pair, which indicates a square on a chess board. Treating
the pair as the starting location of the piece, and its location on the
board as the current position, White is in checkmate. The answer may be
found by reading from the piece making the mate, the black queen on h6,
to the white king on c1. The answer is RSVP.
Across
1. ate sundae, got dizzy, felt ill nauseated
7. support below a fib underlie
10. CBS anchor returns article for nothing nada
11. hearty shape in accord at Elba cordate
12. fight to hear Winslet by the shrine altercate
19. entrance funky aroma door
20. heard a ski resort in the glen vale
22. kitschy bivouac camp
23. music played backward is just average par
24. Roosevelt goes to Nebraska to meet Anderson the one
25. meeting by phone stymies truth honesty
Down
2. obsessive phase of development anal
3. body of water mammal stops short sea
4. the dining man broke the front off the radiator eater
5. sounds like an animal covering a tree fir
6. hiding caused a tentative calm sedate
7. mixed a bad tune at full strength uabated
8. pesticide didn't remove preposition ddt
9. finds a confused sole eating a cat locates
13. Wyatt perfects short listening device earphone
14. migrating late, a blackbird goes for a change, loves it raves
15. pass on a confused mason relay
16. too tall hero giveth strangely overheight
17. "ER" star won't open his mouth for the dentist noah
18. age in several is an individual someone
21. likely to have a short flat apt