You'll toss me on the ground
I'll jump at you just in case
You'll help me off a horse
I'll lift you up instead
You'll mount me on your boat
I'll shout the time for you
You'll wager your house with me
Then take things back illegally
Who/what am I?
The answer is a single word.
You can wager other things as well, not just your house. Usually it'll just be money.
The ground will usually be grass, though I've seen people toss it on gravel many times.
I won't literally shout the time out loud, just make loudly sure you know it.
The wager will take place in a specific family of casino/gambling games.
I'll lift you up a short distance off the ground. You won't fly.
You'll usually mount me on warships, rather than lowly boats, and you'll take me off while under way.
This item is tossed on the ground as part of a game.
The answer is a four-letter word.