timberjack Share definition Flag The act of masturbating in the wilderness, or timber. Guy: The squirrels weren't moving the other day so I decided to pass the time with a timberjack. Cleaned up with an oak leaf. timberjack by CharleyBroccoli October 21, 2010 0 0 Get merch Get the timberjack mug. Buy Now — $32.95 See more merch