look up any word, like guncle:
 
1.
hold and desist
Avast ye scurvy scoundrels! (Will you vitamin C deficient gentlemen please stop what you are doing.)
by Anonymous August 01, 2003
 
2.
A term commonly used by pirates and pirate wannabes. Means cease and desist.
Arr, avast lest ye want yer captain te chop off ye balls!
by Mark November 29, 2004
 
3.
A free antivirus program that i use, developed by Czech computer technology that tends to update your virus database very often, and tell you about it pretty much daily and can get a little annoying, though it is a decent program that works and is free.
Avast! virus database has been updated!
by NoReward October 16, 2011
 
4.
Pirate for "Look at that ass!"
"Avast, Cap'n, thar blows a hearty wench!"
by Dr. Shibby February 02, 2010