An unenforceable contract is one that cannot be enforced because of certain legal defenses against it. true or false

That statement is true.
In most cases, this happen because of the usage of ambiguous language in the contract or a direct violation from the holder.
For example, let's say that you sign a contract to be a singer under management A and would receive 17% Royalty if you do not operate under another management. If you by any chance decided to violate the contract and operate under management B, the 17% royalty from the contract us unenforceable.

Hi my name is bradley i do not have the answer

This category is called mala in se crimes