Synonyms for Hold back:

n.

stamp out, shut off, cut into, kill off, squeeze out, interfere with. call off, forget, back out, cry off, forgo, pull back, inhibit, back down, knock something on the head, think better of something. burden, count against, abstain, bring up against, hesitate, desist, disadvantage, let down, plague, avoid, embarrass. master, deal with, bottle up, manage. obstruct, trap, pin down, pin, immobilize. hoard, store up, stockpile, set-aside, collect. hold back (noun)
suppress, conceal, retain, contain, turn back, hold off, wait, restrain, stop, arrest, keep back, check, hold, keep, hold in.

v.

competition (verb)
check, turn back, stop, contain, arrest.
repress (verb)
suppress, stop, check, hold off, keep back, hold in, keep, restrain, inhibit.

Other synonyms:

cut into, forget, kill off, count against, stamp out, interfere with, bring up against, disadvantage, squeeze out, immobilize, back down, back out, forgo, cry off. shut off, obstruct, call off. pull back, pin down, let down. burden, plague. pin. trap. back down
pull back.
back off
back down.
bottle up
hold in, keep back.
falter
hesitate.
refrain
abstain.
repress
inhibit.
Other relevant words:
avoid, interfere with, abstain, obstruct, hesitate, back down, bottle up, inhibit, let down, arrest, forgo.