Answer:

WHOA

Answer	Crossword Clue
WHOA	Halter for a horse
WHOA	Mountie's command
WHOA	Rider's "Stop!"

WHOA	Dobbin stopper
WHOA	Not so fast!
WHOA	Horse halter
WHOA	"Get the fuck out"
WHOA	Interjection that seemingly no one on the internet can spell correctly
WHOA	Stop
WHOA	Giddyap's opposite
WHOA	"Stop here, Old Paint"

WHOA	"Stop," to Dobbin
WHOA	"Take it easy!"
WHOA	Call to a steed
WHOA	Hold your horses!
WHOA	Command to a team
WHOA	Word shouted to a team
WHOA	"Wait just a minute!"
WHOA	Horse halter?

WHOA	"Slow down, Dobbin!"
WHOA	Arab stopper
WHOA	Stop on the trail
WHOA	"Hold on!"
WHOA	"Hold it, horses!"
WHOA	Arabian stopper
WHOA	"Hold it!"
WHOA	Silver stopper

WHOA	"Halt!"
WHOA	"Not so quick, Silver!"
WHOA	"Just a minute there!"
WHOA	"..., Nellie!"
WHOA	"Hold your horses!"
WHOA	Command to Nellie?
WHOA	Cry from a sleigh seat
WHOA	Horse stopper

WHOA	"Hold on now!"
WHOA	"Stop right there!"
WHOA	"Stop!"
WHOA	Steed stopper
WHOA	Silver halter?