Warning, this verb may not exist. Conjugation is given as example.
Indicative
Present
I don't stiffer you don't stiffer he doesn't stiffer we don't stiffer you don't stiffer they don't stiffer
Present continuous
I'm not stiffering you aren't stiffering he isn't stiffering we aren't stiffering you aren't stiffering they aren't stiffering
Preterite
I didn't stiffer you didn't stiffer he didn't stiffer we didn't stiffer you didn't stiffer they didn't stiffer
Preterite continuous
I wasn't stiffering you weren't stiffering he wasn't stiffering we weren't stiffering you weren't stiffering they weren't stiffering
Present perfect
I haven't stiffered you haven't stiffered he hasn't stiffered we haven't stiffered you haven't stiffered they haven't stiffered
Present perfect continuous
I haven't been stiffering you haven't been stiffering he hasn't been stiffering we haven't been stiffering you haven't been stiffering they haven't been stiffering
Pluperfect
I hadn't stiffered you hadn't stiffered he hadn't stiffered we hadn't stiffered you hadn't stiffered they hadn't stiffered
Pluperfect continuous
I hadn't been stiffering you hadn't been stiffering he hadn't been stiffering we hadn't been stiffering you hadn't been stiffering they hadn't been stiffering
Future
I won't stiffer you won't stiffer he won't stiffer we won't stiffer you won't stiffer they won't stiffer
Future continuous
I won't be stiffering you won't be stiffering he won't be stiffering we won't be stiffering you won't be stiffering they won't be stiffering
Future perfect
I won't have stiffered you won't have stiffered he won't have stiffered we won't have stiffered you won't have stiffered they won't have stiffered
Future perfect continuous
I won't have been stiffering you won't have been stiffering he won't have been stiffering we won't have been stiffering you won't have been stiffering they won't have been stiffering
Conditional
Present
I wouldn't stiffer you wouldn't stiffer he wouldn't stiffer we wouldn't stiffer you wouldn't stiffer they wouldn't stiffer
Present continuous
I wouldn't be stiffering you wouldn't be stiffering he wouldn't be stiffering we wouldn't be stiffering you wouldn't be stiffering they wouldn't be stiffering
Past
I wouldn't have stiffered you wouldn't have stiffered he wouldn't have stiffered we wouldn't have stiffered you wouldn't have stiffered they wouldn't have stiffered
Past continuous
I wouldn't have been stiffering you wouldn't have been stiffering he wouldn't have been stiffering we wouldn't have been stiffering you wouldn't have been stiffering they wouldn't have been stiffering