Bushwhacker

Part of speech: noun (n.)

1. One accustomed to beat about, or travel through, bushes. [U.S.] They were gallant bushwhackers, and hunters of raccoons by moonlight. W. Irving.

2. A guerrilla; a marauding assassin; one who pretends to be a peaceful citizen, but secretly harasses a hostile force or its sympathizers. [U.S.] Farrow.