The 1986 comedy film ____ Apocalypse starred Loretta Swit, Herbert Lom and Peter Cook (6)
I believe the answer is:
whoops
(Other definitions for whoops that I've seen before include "Exclamation after making a mistake" , "Oh dear! That was a mistake!" , "Yikes, I've dropped something!" , "Loud cries of excitement" , "Something said after minor accident or mistake" .)