'ill-formed' definitions:

Definition of 'ill-formed'

From: WordNet
adjective
Not grammatical; not conforming to the rules of grammar or accepted usage [syn: ungrammatical, ill-formed] [ant: grammatical, well-formed]

Definition of 'ill-formed'

From: GCIDE
  • ill-formed \ill-formed\ adj.
  • 1. (Grammar) not grammatical; ungrammatical; not conforming to the rules of grammar or accepted usage. Opposite of grammatical.
  • Syn: ungrammatical. [WordNet 1.5]