scare the hell out of
do someone a frighten
spook out
jump in one's skin
crap one's pants
piss one's pants
spook
fearing
flay
frighten the piss out of
timorsome
overfrighten
fearful
funk
put the wind up
poopless
terrify
scare someone to death
fear
frightenable
frighten the life out of someone
scare the shit out of
frightsomeness
terrifiedness
scareful
brick it
frightfulness
make someone's hair stand on end
ph33r
frightenedness
have the wind up
startful
out of one's skin
chill
scared
flaysome
quiver
tremble
frisson
run scared
frightened
thrill
shudder
fray
shiver
tingle
fearmonger
apprehend
eerie
frightenedly