vehementer

Vehementer is the adverb of the adjective vehemens, vehementis, third declension one-termination. Regular comparative and superlative: vehementius, vehementissime. The old folk etymology from vehe- plus mens, "carried out of one's mind", is charming and almost certainly wrong, but it does describe the word's flavour.

Two registers, and Latin uses both without embarrassment. With verbs of physical action it means "violently, forcefully": ventus vehementer flat. With verbs of feeling or thinking it drains to a plain intensifier, "very, greatly", where English would say strongly: vehementer erras is simply "you are quite wrong", no shouting implied. Cicero uses it in the second sense constantly in his letters. English vehement kept only the angry half.