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