7. Illegal and Uncertain Agreements

The last post covered Section 23's six grounds for an unlawful consideration or object. This post looks closely at one distinction students often miss inside that same territory — void is not the same as illegal, even though every illegal agreement is also void — and then covers a completely separate ground for failure that has nothing to do with unlawfulness at all: an agreement whose terms are simply too vague to enforce.

Void vs. Illegal — Why the Difference Matters

Every illegal agreement is void, but not every void agreement is illegal. The practical difference shows up in collateral transactions — agreements connected to, but separate from, the main one. If the main agreement is merely void (for a reason short of actual illegality, such as being a wager), a separate, collateral agreement connected to it is not automatically tainted. If the main agreement is illegal, the taint spreads — collateral transactions knowingly entered into to further the illegal purpose are unenforceable too.

Wagering Agreements — Section 30

Section 30 makes agreements by way of wager void, and no suit can be brought to recover anything won on a wager. A wagering agreement is a mutual promise where each side stands to win or lose depending purely on the outcome of an uncertain future event, in which neither party has any real interest except the stake itself.

• Section 30: wagering agreements are void, not enforceable — but Gherulal Parakh confirms they are not "illegal" in the stricter sense used for Section 23's other grounds
• A collateral agreement connected to a void (but not illegal) main agreement generally survives; a collateral agreement connected to a genuinely illegal main agreement is tainted along with it

Uncertain Agreements — Section 29

Section 29 takes a completely different route to unenforceability: agreements whose meaning is not certain, or capable of being made certain, are void — not because anything about them is unlawful, but because a court simply cannot work out what the parties actually promised to do.

• "Capable of being made certain" is the key phrase — if the agreement itself supplies a method to resolve the apparent uncertainty (for example, a formula, a trade custom, or a reference to a specific market rate), Section 29 doesn't apply, even though the price wasn't stated as one fixed figure
• Section 29 is a distinct ground from mistake (Sections 20–22): in mistake, the parties are wrong about a fact; in uncertainty, the terms themselves never fixed a workable meaning in the first place

A Practical Example

X agrees to sell B his Maruti car for ₹50,000 or ₹1,00,000, with nothing in the agreement to indicate which of the two prices was meant. Is the agreement valid? Applying Section 29: this is exactly the kind of agreement the section targets — the price term has no fixed, ascertainable meaning, and nothing within the agreement itself resolves which figure applies. The agreement is void for uncertainty, regardless of whether X and B otherwise genuinely intended to strike a deal.

Quick Revision Points

• Every illegal agreement is void, but not every void agreement is illegal — the difference matters for collateral transactions, which survive a merely-void main agreement but not a genuinely illegal one
• Section 30: wagering agreements are void; Gherulal Parakh v. Mahadeodas Maiya confirms they are void but not illegal/immoral under Section 23
• Section 29: agreements whose meaning is uncertain, and not capable of being made certain, are void — a completely separate ground from unlawfulness or mistake
• An agreement that supplies its own way of resolving apparent uncertainty (a formula, custom, market reference) is not void under Section 29