From non- + flavonoid.
nonflavonoid (plural nonflavonoids)
- A substance that is not a flavonoid.
2015 July 23, Bruno Amato et al., “Aterofisiol® in carotid plaque evolution”, in Drug Design, Development and Therapy[1], volume 9, →DOI:Resveratrol (3,5,4′-trihydroxy- trans -stilbene) is a nonflavonoid polyphenolic compound belonging to the stilbene group able.