Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I must frighten frighten you must frighten frighten he must frighten frighten we must frighten frighten you must frighten frighten they must frighten frighten
V-ing form
I must be frighten frightening you must be frighten frightening he must be frighten frightening we must be frighten frightening you must be frighten frightening they must be frighten frightening
Perfect
I must have frighten frightened you must have frighten frightened he must have frighten frightened we must have frighten frightened you must have frighten frightened they must have frighten frightened
V-ing perfect
I must have been frighten frightening you must have been frighten frightening he must have been frighten frightening we must have been frighten frightening you must have been frighten frightening they must have been frighten frightening
Negation
Simple form
I must not frighten frighten you must not frighten frighten he must not frighten frighten we must not frighten frighten you must not frighten frighten they must not frighten frighten
V-ing form
I must not be frighten frightening you must not be frighten frightening he must not be frighten frightening we must not be frighten frightening you must not be frighten frightening they must not be frighten frightening
Perfect
I must not have frighten frightened you must not have frighten frightened he must not have frighten frightened we must not have frighten frightened you must not have frighten frightened they must not have frighten frightened
V-ing perfect
I must not have been frighten frightening you must not have been frighten frightening he must not have been frighten frightening we must not have been frighten frightening you must not have been frighten frightening they must not have been frighten frightening
Interrogative form
Simple form
must I frighten frighten? must you frighten frighten? must he frighten frighten? must we frighten frighten? must you frighten frighten? must they frighten frighten?
V-ing form
must I be frighten frightening? must you be frighten frightening? must he be frighten frightening? must we be frighten frightening? must you be frighten frightening? must they be frighten frightening?
Perfect
must I have frighten frightened? must you have frighten frightened? must he have frighten frightened? must we have frighten frightened? must you have frighten frightened? must they have frighten frightened?
V-ing perfect
must I have been frighten frightening? must you have been frighten frightening? must he have been frighten frightening? must we have been frighten frightening? must you have been frighten frightening? must they have been frighten frightening?
Interro-negative form
Simple form
must I not frighten frighten? must you not frighten frighten? must he not frighten frighten? must we not frighten frighten? must you not frighten frighten? must they not frighten frighten?
V-ing form
must I not be frighten frightening? must you not be frighten frightening? must he not be frighten frightening? must we not be frighten frightening? must you not be frighten frightening? must they not be frighten frightening?
Perfect
must I not have frighten frightened? must you not have frighten frightened? must he not have frighten frightened? must we not have frighten frightened? must you not have frighten frightened? must they not have frighten frightened?
V-ing perfect
must I not have been frighten frightening? must you not have been frighten frightening? must he not have been frighten frightening? must we not have been frighten frightening? must you not have been frighten frightening? must they not have been frighten frightening?