nonill

Nonill is a term used in discussions of grammaticality to denote strings that are not ill-formed according to a given grammar. It is a neologism rather than an established category in standard linguistics, and is often introduced in theoretical or pedagogical contexts to contrast with ill-formed sentences. The concept is treated here as a hypothetical construct for illustration.

Origin and usage: The term appears in online linguistics discussions and in experimental works from the early 2020s as playful shorthand for “not ill-formed.” Its precise definition varies with the grammar or formalism in use, and different frameworks may set different thresholds for features that count as acceptable.

Definition and criteria: A string is nonill if it conforms to the syntactic and morphophonological constraints of the targeted grammar. Nonill strings can still be semantically odd, pragmatically awkward, or ambiguous, but they do not violate the structural rules that would render them ill-formed.

Examples: The cat sat on the mat is nonill under standard English grammars. The sentence Colorless green ideas sleep furiously is nonill in a framework that accepts syntactically valid but semantically unusual strings. An ill-formed example would be The cat sat on, which lacks a required complement, or Cat the the sat on mat, which violates basic word order rules.

Applications and relevance: The concept is used in discussions of parser design, error handling, and linguistic pedagogy to separate syntactic well-formedness from semantics and pragmatics.

See also: Grammaticality, well-formed formula, ill-formed sentence, syntax, semantics.