Fishy (adjective)

1. Suspicious or questionable; having the appearance of being false or deceitful.
2. Resembling or characteristic of fish, especially in smell or taste.

Origin:

Derived from the old english word "fisc" meaning fish. it is also related to the dutch word "visch" and the german word "fisch" which also have the same meaning.

Examples:

1. The story he told me seemed fishy, so I decided to investigate further.
2. The fishy smell coming from the river made it clear that the water was polluted.
3. The alibi that he gave the police seemed fishy and they were not convinced.
4. The fishy taste of the seafood made it clear that it was not fresh.
5. The fishy looking man standing on the corner seemed out of place.