Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could pay off you could pay off he could pay off we could pay off you could pay off they could pay off
V-ing form
I could be pay offing you could be pay offing he could be pay offing we could be pay offing you could be pay offing they could be pay offing
Perfect
I could have pay offed you could have pay offed he could have pay offed we could have pay offed you could have pay offed they could have pay offed
V-ing perfect
I could have been pay offing you could have been pay offing he could have been pay offing we could have been pay offing you could have been pay offing they could have been pay offing
Negation
Simple form
I could not pay off you could not pay off he could not pay off we could not pay off you could not pay off they could not pay off
V-ing form
I could not be pay offing you could not be pay offing he could not be pay offing we could not be pay offing you could not be pay offing they could not be pay offing
Perfect
I could not have pay offed you could not have pay offed he could not have pay offed we could not have pay offed you could not have pay offed they could not have pay offed
V-ing perfect
I could not have been pay offing you could not have been pay offing he could not have been pay offing we could not have been pay offing you could not have been pay offing they could not have been pay offing
Interrogative form
Simple form
could I pay off? could you pay off? could he pay off? could we pay off? could you pay off? could they pay off?
V-ing form
could I be pay offing? could you be pay offing? could he be pay offing? could we be pay offing? could you be pay offing? could they be pay offing?
Perfect
could I have pay offed? could you have pay offed? could he have pay offed? could we have pay offed? could you have pay offed? could they have pay offed?
V-ing perfect
could I have been pay offing? could you have been pay offing? could he have been pay offing? could we have been pay offing? could you have been pay offing? could they have been pay offing?
Interro-negative form
Simple form
could I not pay off? could you not pay off? could he not pay off? could we not pay off? could you not pay off? could they not pay off?
V-ing form
could I not be pay offing? could you not be pay offing? could he not be pay offing? could we not be pay offing? could you not be pay offing? could they not be pay offing?
Perfect
could I not have pay offed? could you not have pay offed? could he not have pay offed? could we not have pay offed? could you not have pay offed? could they not have pay offed?
V-ing perfect
could I not have been pay offing? could you not have been pay offing? could he not have been pay offing? could we not have been pay offing? could you not have been pay offing? could they not have been pay offing?