Definition from Wiktionary, the free dictionary
From Middle English noy + -some (short for annoy, from an(n)oien, enoien from Anglo-Norman anuier, from Old French enuier (French: ennuyer), from Late Latin inodiare (to make hateful), from in- (intensive prefix) + odium (hate). 
- Morally hurtful or noxious.
- Hurtful or noxious to health; unwholesome, insalubrious.
- Offensive to the senses; disgusting, unpleasant, nauseous; foul, fetid, especially having an undesirable smell; sickening, nauseating.
- For usage examples of this term, see Citations:noisome.
- See also Wikisaurus:harmful
morally hurtful or noxious
hurtful or noxious to health
offensive to the senses