what's a contract?

Question 1

what’s an onerous obligation

Answer 1

where both parties undertake obligations and there is an exchange of performance.

Question 2

Gratuitous (sometimes called ‘unilateral’ – but note controversy)

Answer 2

only one party is obliged to perform (even though both of them agreed the contract);

Question 3

general rules of promise

Answer 3

The person making the promise (promisor) must clearly intend to be legally bound by it – they want to keep their promise.
This intention must be expressed clearly, using precise words (as seen in the case Regus).
Just expressing this intention is enough to create a binding obligation.
The person receiving the promise (promisee) doesn’t need to accept it, act on it, know about it, or even exist when it’s made. They automatically have the right to the promise.
The promisor doesn’t need to get anything in return for making the promise.
A promise can depend on a condition being met, but the promisor is still bound by the promise, not by the condition