1: Physicist failed to finish food before a trip round sun (7)
2: 'Naked Gun' actor prepares to be dubbed in (in soundtrack) (7)
3: Incredibly stoned, taking Intro to Math final (7)
4: A cold fish embraces that woman's mortal weaknesses (8,5)
5: Fuss over band amounts to worshipping! (7)
6: In my greed I blessed food (7)
7: Almost useless nags (7)
10: Monarch met monarch in even open space for coin-operated machines (7,6)
15: Mean to declare how old you are (7)
16: One out of three released after misstep (7)
17: Outdoors running on a pier (4,3)
19: Deep sleep, father recalled, is fitting (7)
20: Affair? Despair soon dies, in steps. (7)
21: Appreciate it: a large data format (7)