Noah Webster's New International Dictionary of the English Language

1. (superl.) Somewhat sick; disposed to illness; attended with disease; as, a sickly body.

2. (superl.) Producing, or tending to, disease; as, a sickly autumn; a sickly climate.

3. (superl.) Appearing as if sick; weak; languid; pale.

4. (superl.) Tending to produce nausea; sickening; as, a sickly smell; sickly sentimentality.

5. (adv.) In a sick manner or condition; ill.

6. (v. t.) To make sick or sickly; -- with over, and probably only in the past participle.