In a burning manner; with intense heat, passion, or urgency; fervently or acutely.
From 'burning' (present participle of burn) + -ly, the adverbial suffix. Has been in use since at least the 16th century to describe intense emotional or physical states.
Poets used 'burningly' to describe forbidden love and religious passion—it appears repeatedly in 17th-century love poetry as an ultra-dramatic way to express emotional intensity!
Complete word intelligence in one call. Free tier — 50 lookups/day.