What does disallow mean?
Disallow is a formal verb meaning to prohibit, reject, or declare something not permissible. It is commonly used for actions, objects, or proposed plans that official rules do not permit: a regulation may disallow parking on a pavement, while a committee may disallow a proposal. The word can also describe the refusal of permission or the denial of a claim, giving it a firm and sometimes bureaucratic tone. Although disallow can be used in everyday conversation, it is more characteristic of legal, institutional, and administrative language than of informal speech. It is usually transitive, as in “The policy disallows the use of outside materials.” Compared with forbid, disallow can sound especially procedural, and compared with discourage, it indicates a clear rule rather than a preference. The prefix dis- makes the word’s meaning transparent: to disallow something is to not allow it.
verbTo prohibit, reject, or declare something not permissible. It can also mean to deny a request, claim, or proposed action.
- To prohibit or declare something not permissible, especially in rules, regulations, or policies.
- To refuse permission for an action or to reject a proposed plan.
- To declare something invalid, unacceptable, or ineligible.
"The regulations explicitly disallow the use of mobile phones during the examination."
"The school disallows students from bringing bicycles into the main building."
"The committee disallowed the proposal after several members objected to its cost."
Disallow is a firm, often institutional way of saying “do not permit”—it closes a door rather than merely discouraging the action.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does disallow come from?
Disallow is an English formation combining the prefix dis- with allow, giving it the literal sense “not allow.” The underlying word allow came into Middle English from Old French aloer, ultimately from Latin allocare, meaning “to assign” or “to allot,” and its meaning developed toward permitting. Disallow historically expressed the idea of denying permission or refusing approval, a use that continues in modern rules, laws, and institutional decisions. It belongs to the same etymological family as allow, allowable, and allowance.
Related word forms
How disallow is actually used
Disallow is primarily formal and is especially common in legal, institutional, and administrative contexts. It is generally stronger and more definite than discourage, and it usually takes a direct object.
Easily confused with disallow
Disallow means to prohibit or refuse permission, whereas dispel means to drive away or eliminate a fear, rumor, or difficulty.