Antonyms of adj well-defined

2 senses of well-defined

Sense 1
chiseled, well-defined -- (having a clean and distinct outline as if precisely cut along the edges; "a finely chiseled nose"; "well-defined features")

INDIRECT (VIA distinct) -> indistinct -- (not clearly defined or easy to perceive or understand; "indistinct shapes in the gloom"; "an indistinct memory"; "only indistinct notions of what to do")

Sense 2
well-defined (vs. ill-defined), clear -- (accurately stated or described; "a set of well-defined values")

ill-defined (vs. well-defined), unclear -- (poorly stated or described; "he confuses the reader with ill-defined terms and concepts")

Similarity of adj well-defined

2 senses of well-defined

Sense 1
chiseled, well-defined -- (having a clean and distinct outline as if precisely cut along the edges; "a finely chiseled nose"; "well-defined features")
       => distinct (vs. indistinct) -- (easy to perceive; especially clearly outlined; "a distinct flavor"; "a distinct odor of turpentine"; "a distinct outline"; "the ship appeared as a distinct silhouette"; "distinct fingerprints")

Sense 2
well-defined (vs. ill-defined), clear -- (accurately stated or described; "a set of well-defined values")