wrench in the works

noun 0.862

spanner

noun 0.759

fly in the ointment

noun 0.628

monkey wrench

noun 0.599

wrench

noun 0.593

troublemaker

noun 0.591

disrupter

noun 0.549

destabilizer

noun 0.541

disturber

noun 0.533

tough nut to crack

noun 0.530

troubler

noun 0.530

interfering

noun 0.527

sticky wicket

noun 0.525

mess-up

noun 0.523

haywire

noun 0.523

loose cannon

noun 0.521

screwup

noun 0.520

disruption

noun 0.518

pain in the arse

noun 0.515

stumper

noun 0.512

troublemaking

noun 0.512

showstopper

noun 0.511

joker in the pack

noun 0.511

contretemps

noun 0.510

troubleshooter

noun 0.508

bother

noun 0.507

sabotage

noun 0.506

twist of fate

noun 0.506

can of worms

noun 0.504

hindrance

noun 0.503

screw

noun 0.503

accident waiting to happen

noun 0.503

bugger

noun 0.501

screwball

noun 0.501

interference

noun 0.500