1: A chair may be material (5)
4: California business providing front for fraudulent racket (9)
6: Runner or dramatist in play (13)
10: Banker maintains a Greek swimmer (7)
11: Fell limply and quietly in a squalid area extremely exhausted (7)
12: Irresponsible friends show up merry (9)
14: That terrific ingot has a sweetener (5)
16: Bury in the empty sepulcher, eventually (5)
17: Greek hero's a stranger among men (9)
19: Detains stranger as a substitute (7)
21: Titanic, once alerted, hugs harbor (7)
23: Does not see the advertisement because it is in the wrong section. (13)
24: Emphatic rejection of one joy was unusual (2,3,4)
25: In Germany, the monster returned from the east. (5)