ACROSS
 1. <make founder {sink}> SCUTTLE <act like hermit {crab}>
 5. WH_ IFFY = WHIFFY <bad-smelling>
 8. <waterspout climber> SPIDER = ←REDIPS←
 9. <officer> CORPORAL <material>
10. <poet's peninsula> CHERSONESE = (.t)CHER'S ONE SE(a.)
11. <monster from the Himalayas> YETI = YET + I
12. <Brazil state> ACRE <land area>
13. S WEE THE ART = SWEETHEART <dear>
15. <copy> RECREATION <fun activity>
18. "HAIL" = HALE <sound>
20. <experienced texture of> FELT <soft fabric>
22. ACCIDENTAL, O←A = OCCIDENTAL <western>
24. <sparkling white {wine}> CHAMPERS <teeth?>
25. <mischievous kid> URCHIN = [-l]URCHIN[-g]
26. (.n)A THE NA(t.) = ATHENA <goddess>
27. BANG after SHE = SHEBANG <affair>

DOWN
 1. <lesbian> SAPPHIC = C after (SAP + PHI)
 2. <say jocks> UNDERWEAR = [-s]UNDER [-s]WEAR
 3. "TORE SEW" = TORSO <upper body>
 4. <put out> EXCRETE = EX + CRETE
 5. <description of bad apple, perhaps> WORM-EATEN = W OR MEAT + E_N
 6. IV O + ←YR← = IVORY <dominoes, once?>
 7. <more insipid> FLATTER <praise>
13. SO + A POP ERA = SOAP OPERA <drama>
14. E CHINA _CEA_ = ECHINACEA <plant called coneflower>
16. E YES HOT = EYESHOT <range of onlookers>
17. <cuts> INCISES = "INN SIZES"
19. <first> LEADING <blank space on page {"ledding"}>
21. TEMPER - R = TEMPE <Arizona city>
23. <two> DEUCE = DE[-d]UCE