All major league contracts are guaranteed. So are NBA. NFL contracts are not guaranteed.
The non-team option years are.
The difference is the Union. The NBA have guaranteed salaries in their CBA (Collective Bargaining Agreement). The NFL does not have clauses that guarantee the entire salary, but the signing bonuses are the guaranteed portion of their contracts.
All pro sports except for football have guaranteed contracts.
Not all of them
No contracts are guaranteed.
No. Guaranteed contracts are forbidden under the NFL's bargaining agreements with its players. Guaranteed portions of contracts are allowed, as are signing bonuses.
They are guaranteed a profit.
as much as it says in their contracts