Faintly or unclearly perceived; indistinct:
Not clear, distinct, or precise; blurred
Unclear, obscure, cryptic, etc.
Find another word for ill-defined. In this page you can discover 16 synonyms, antonyms, idiomatic expressions, and related words for ill-defined, like: indistinct, clouded, dim, fuzzy, murky, obscured, unclear, vague, well-defined, unspecific and imprecise.