spank

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To slap on the buttocks with a flat object or with the open hand, as for punishment.
2. v. To move briskly or spiritedly.
3. n. A slap on the buttocks.

Century Dictionary and Cyclopedia

1. To move with a quick springing step between a trot and a gallop; move quickly and with spirit. See spanking.
2. To strike with the open hand, or with something flat and hard; slap with force on the buttocks.
3. To urge by slapping or striking; impel forcibly; drive; produce some specified effect upon by spanking or slapping.
4. To pound, beat, or slap the water in sailing, as a boat.
5. n. A sounding blow with the open hand or something flat, especially upon the buttocks.

Wiktionary

1. v. transitive To beat, smack or slap a person's buttocks, with the bare hand or other object, as punishment, gesture or form of sexual interaction.
2. v. transitive To soundly defeat, to trounce.
3. v. intransitive To move rapidly.
4. n. An instance of spanking, separately or part of a multiple blows-beating; a smack, swat or slap.
5. n. A slapping sound, as produced by spanking.

GNU Webster's 1913

1. v. To strike, as the breech, with the open hand; to slap.
2. n. A blow with the open hand; a slap.
3. v. To move with a quick, lively step between a trot and gallop; to move quickly.

WordNet 3.0

1. v. give a spanking to; subject to a spanking
2. n. a slap with the flat of the hand