Impetuous, a.
Etymology: [F. impetueux, L. impetuosus. See Impetus.]
1. Rushing with force and violence; moving with impetus; furious; forcible; violent; as, an impetuous wind; an impetuous torrent. Went pouring forward with impetuous speed. Byron.
2. Vehement in feeling; hasty; passionate; violent; as, a man of impetuous temper. The people, on their holidays, Impetuous, insolent, unquenchable. Milton.
Syn. -- Forcible; rapid; hasty; precipitate; furious; boisterous; violent; raging; fierce; passionate. -- Im*pet"u*ous*ly, adv. -- Im*pet"u*ous*ness, n.
Shades of meaning
Fernald has no entry of its own for impetuous; he lists it under eager, fierce.
He lists it without comment; the entries above explain its neighbors.