Containing omens.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (adjective) (adj.) (adjective)
Containing a sign or token for good or evil.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (adjective) (adj.) (adjective)

Usage examples:

She lay still, perfectly still, with something ill- omened and unnatural in her attitude.
- 'Twixt Land & Sea by Joseph Conrad
He laughed again in his ill- omened fashion and went on hurriedly, as though he feared that he should be called upon to explain his words: " Where is the fee?
- Child of Storm by H. Rider Haggard
For though Courtier knew that against an unpopular idea there must always be a majority, he never thought so ill of any individual as to suppose him capable of belonging to that ill- omened body.
- The Patrician by John Galsworthy