bottle it
dishearten
gut up
nut up
throttle down
tamp down
puss out
lose one's nerve
fight down
reprove
choke back
box and lock
disincentivize
take the wind out of someone's sails
internalize
contradict
unmotivate
apostatise
tergiversate
apostatize
wear
repulse
save one's breath to cool one's porridge
silence
bottle
show the white feather
gag
chicken out
cut someone cold
throw something in someone's face
spit it out
let someone down gently
scruple
squash
mislike
disbelieve
cramp someone's style
cede the field
borrow
cut
cold-shoulder
cut the ground from under someone's feet
daunt
scare
lose control
recant
demotivate
bottle out
put the fear of God into
dash
frighten away
put one's foot down upon
scare off
harumph
scare away
piss on someone's bonfire
put one's foot down on
pall
frighten off
rain on someone's parade
protest too much
redlight
take steps
wimp out