Suspicious, or of dubious character.
Experiencing or showing doubt, sceptical.
Subject to, or causing doubt.
Improbable or unlikely.
Unclear or unreliable.
Undecided or of uncertain outcome.
A doubtful person or thing.
Having a quality that arouses suspicion.
Having signs that suggest a design problem; having a code smell.
Having a bad smell.
a Short Magazine Lee Enfield rifle or one of its derivatives.