snarl up verb 5snarl-up noun 1forms 4 verb5 •to entangle •To block (traffic); to cause (traffic) to be congested. •to become congested. •To become tangled; to become entangled •To put into disarray; contort; confuse; muddle up snarl-up noun1 •(UK, Australia) A traffic jam. formssnarled up · snarling up · snarls up · snarl-ups