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