stiffen [v.]
-stiffen
Istiffen
youstiffen
hestiffens
westiffen
youstiffen
theystiffen
Istiffened
youstiffened
hestiffened
westiffened
youstiffened
theystiffened
Iwillstiffen
youwillstiffen
hewillstiffen
wewillstiffen
youwillstiffen
theywillstiffen
Ihavestiffened
youhavestiffened
hehasstiffened
wehavestiffened
youhavestiffened
theyhavestiffened
-stiffening
-stiffened