heart-burning1
/ˈhɑːtˌbəːnɪŋ/noun
1An angry and embittered state of mind, felt but not openly expressed; rankling jealousy, resentment, or discontent.
2In plural Feelings of jealousy, resentment, or bitterness; grudges.
Origin
Late Middle English; earliest use found in The Laud Troy Book. From heart + burning.
heart-burning2
/ˈhɑːtˌbəːnɪŋ/Now archaic or literary
adjective
That arouses strong emotions, especially jealousy, bitterness, or resentment; resulting from or characterized by such emotions. Of an emotion: painfully sharp or intense; deeply felt.
Origin
Late 16th century; earliest use found in Edmund Spenser (?1552–1599), poet and administrator in Ireland. From heart + burning, probably after heart-burn, heart-burning.