1. A reference to behaving in an unacceptable manner: Running into the house with muddy feet is a very errantic activity and it is not at all the right thing to do.
2. Descriptive of anyone or anything wandering from an intended course, or not reaching an intended destination: When the engine died, the car coasted in a most errantic manner down the hill and stopped before hitting a tree.
3. Related to roving in search of adventure and romance: Jason enjoyed a most errantic summer holiday with just a backpack and a train ticket.