Answer:

SICEM

Answer	Crossword Clue
SICEM	"Bite, boy!"
SICEM	Opposite of "Down, boy!"
SICEM	Order to a shepherd

SICEM	"Attack, Shep!"
SICEM	Command to an attack dog
SICEM	Guard dog command
SICEM	"Attack!"
SICEM	Order to a boxer
SICEM	Order to pounce
SICEM	Unlikely command to a Chihuahua
SICEM	Command to a junkyard dog

SICEM	Attack command
SICEM	Order to a guard dog
SICEM	Shout to Fido
SICEM	Command to Fido
SICEM	Command to a guard dog
SICEM	"Attack, boy!"
SICEM	Words to a Doberman
SICEM	Attack order

SICEM	"Go for the jugular!"
SICEM	Command to a canine
SICEM	"Attack, Rover!"
SICEM	Order to attack
SICEM	Attack-dog command
SICEM	Biting order
SICEM	Attack dog command
SICEM	Words to a boxer

SICEM	Command to a police dog
SICEM	"Attack, Rex!"
SICEM	"Attack, Fido!"
SICEM	Words a house burglar doesn't want to hear
SICEM	Words to an attack dog
SICEM	Canine command
SICEM	Command to a Doberman
SICEM	Order countermanded by "Down, boy!"

SICEM	Biting remark?
SICEM	Dog command
SICEM	'Attack, Fido!'
SICEM	'Attack, Spot!'
SICEM	Doberman command