wrench in the works

noun 0.629

spanner in the works

noun 0.628

gadfly

noun 0.576

big fly

noun 0.555

trouble spot

noun 0.553

sticking point

noun 0.552

thorn in the flesh

noun 0.552

flyspeck

noun 0.549

bad apple

noun 0.547

nuisance

noun 0.539

niggle

noun 0.535

stumbling block

noun 0.534

sticky wicket

noun 0.534

pain in the arse

noun 0.531

fly

noun 0.529

bone of contention

noun 0.528

pet peeve

noun 0.526

hindrance

noun 0.523

apple of discord

noun 0.521

troublemaker

noun 0.521

deal breaker

noun 0.519

pain in the butt

noun 0.519

bone to pick

noun 0.518

impediment

noun 0.517

nitpicker

noun 0.515

bugbear

noun 0.514

housefly

noun 0.513

obstacle

noun 0.512

flaw

noun 0.510

quibble

noun 0.509

bad egg

noun 0.509

fruit fly

noun 0.508

annoying

noun 0.506

bug

noun 0.506

wet blanket

noun 0.506

fly out

noun 0.506

bother

noun 0.505

bugging

noun 0.502

blackfly

noun 0.501