1: Causes distress

6: Undercover worker

9: TV spy Maxwell

14: Tornado siren, e.g.

15: Deep distress

16: Undeliverable letter, to a postal worker

17: Betray contempt

18: For ___ the marbles

19: Charged particle

20: Hazarding a guess: doughy metaphysician?

23: Biathlon need

24: Droop

25: Tag players

28: Inscribe with acid

31: Railroad station porter

36: Adviser

39: LED part

40: Wild about

41: Boxers' wraps

43: Hunter's quarry

44: Geeks

46: Rhymester

48: Fathoms

50: Hurt, as a knee

51: November winners

52: Get going

54: Cut off

56: Experience a lack of oxygen, perhaps

64: Suitor

65: 'PUSH FOR ___'

66: Dubbed

67: Point of view

68: Dance part?

69: Used a keyboard

70: Revue segments

71: Little one

72: Impudent

1: Door clasp

2: Arm bone

3: Tape spool

4: Giant sequoias, e.g.

5: Golfer's count

6: Smack, as a baseball

7: Game on horseback

8: Hollers

9: Acquired by acting quickly

10: Revealing dress

11: World War II partnership

12: Civil unrest

13: Half a score

21: Compound in fireworks

22: Crew implement

25: Cake cover

26: Photocopier ink

27: 'Kama ___' (Hindu love manual)

29: Hoof-on-pavement sound

30: Kings of the road

32: Excavates

33: Ring-tailed animal

34: Commercial creators

35: Equals

37: Acknowledges silently

38: Be a stinker

42: Circus prop

45: Heavenly bodies

47: Applies holy oil to

49: Churchill's title

53: Throw out in the street

55: Acapulco attraction

56: Goose sound

57: Ranger Smith's cartoon nemesis

58: Hit with hailstones

59: Sound on the rebound

60: 'Far out!'

61: Band boxes?

62: Golf ball pegs

63: Small whirlpool

64: Used to be