skirmish

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A minor battle in war, as one between small forces or between large forces avoiding direct conflict.
• noun A minor or preliminary conflict or dispute.
• intransitive verb To engage in a minor battle or dispute.

from The Century Dictionary.

• noun An irregular fight, especially between small parties; an engagement, in the presence of two armies, between small detachments advanced for the purpose either of drawing on a battle or of concealing by their fire the movements of the troops in the rear.
• noun Defense.
• noun Any contention or contest; a preliminary trial of strength, etc.
• noun Synonyms Rencounter, Brush, etc. See encounter.
• To fight irregularly, as in a skirmish; fight in small parties or along a skirmishline.
• To defend one's self; strike out in defense or attack.
• To be in a position of guarded and cautious attack; fence.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To fight slightly or in small parties; to engage in a skirmish or skirmishes; to act as skirmishers.
• noun A slight fight in war; a light or desultory combat between detachments from armies, or between detached and small bodies of troops.
• noun A slight contest.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun military A brief battle between small groups, usually part of a longer or larger battle or war.
• noun figuratively By extension, any minor dispute.
• noun A type of outdoor military style game using paintball or similar weapons.
• verb To engage in a minor battle or dispute

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a minor short-term fight
• verb engage in a skirmish