Sketchy (adjective)

1. Not clearly or fully detailed or explained; incomplete.
2. Not reliable or trustworthy.

Origin:

Early 20th century: from sketch + -y.

Examples:

1. The information was sketchy.
2. The details of the plan were sketchy.
3. His alibi was sketchy and not believable.
4. The report was sketchy and inconclusive.
5. The map was sketchy and not very helpful.