Appel Ap`pel", n. [F., prop., a call. See Appeal, n.] (Fencing) A tap or stamp of the foot as a warning of intent to attack; -- called also attack., Attack At*tack", v. i. To make an onset or attack., Attack At*tack", v. t. [imp. & p. p. Attacked; p. pr. & vb. n. Attacking.] [F. attaquer, orig. another form of attacher to attack: cf. It. attacare to fasten, attack. See Attach, Tack a small nail.] 1. To fall upon with force; to assail, as with force and arms; to assault. ``Attack their lines.' --Dryden. 2. To assail with unfriendly speech or writing; to begin a controversy with; to attempt to overthrow or bring into disrepute, by criticism or satire; to censure; as, to attack a man, or his opinions, in a pamphlet. 3. To set to work upon, as upon a task or problem, or some object of labor or investigation. 4. To begin to affect; to begin to act upon, injuriously or destructively; to begin to decompose or waste. On the fourth of March he was attacked by fever. --Macaulay. Hydrofluoric acid . . . attacks the glass. --B. Stewart. Syn: To Attack, Assail, Assault, Invade. Usage: These words all denote a violent onset; attack being the generic term, and the others specific forms of attack. To attack is to commence the onset; to assail is to make a sudden and violent attack, or to make repeated attacks; to assault (literally, to leap upon) is to attack physically by a had-to-hand approach or by unlawful and insulting violence; to invade is to enter by force on what belongs to another. Thus, a person may attack by offering violence of any kind; he may assail by means of missile weapons; he may assault by direct personal violence; a king may invade by marching an army into a country. Figuratively, we may say, men attack with argument or satire; they assail with abuse or reproaches; they may be assaulted by severe temptations; the rights of the people may be invaded by the encroachments of the crown.