noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   plural of hardhead form-of, plural
2. 2
   a weedy perennial with tough wiry stems and purple flowers; native to Europe but widely naturalized wordnet

Synonyms

All synonyms

black knapweedcentaurea nigralesser knapweedlesser knapweed

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.