1) Angry boxer 2) Angry canine 3) Angry dog 4) Beware of dog dog 5) Cur, at times 6) Guard dog 7) Junkyard dog, often 8) Mean dog, at times 9) Menacing dog 10) Stage villain, often 11) Teeth-baring mutt 12) Watchdog 13) Watchdog, at times 1) Cur 
• (n.) One who snarls; a surly, growling animal; a grumbling, quarrelsome fellow. • (n.) One who makes use of a snarling iron.
Snarl'er noun One who snarls; a surly, growling animal; a grumbling, quarrelsome fellow. 
Snarler is Australian slang for a discharge.