What does "erratic" mean?

Additional senses

1. 2.Irregular; changeable. "Erratic fever." Harvey. Erratic blocks, gravel, etc. (Geol.), masses of stone which have been transported from their original resting places by the agency of water, ice, or other causes. -- Erratic phenomena, the phenomena which relate to transported materials on the earth's surface.
2. 3.One who deviates from common and accepted opinions; one who is eccentric or preserve in his intellectual character.
3. 4.A rogue. [Obs.] Cockeram.
4. 5.(Geol.) Any stone or material that has been borne away from its original site by natural agencies; esp., a large block or fragment of rock; a bowlder. Note: In the plural the term is applied especially to the loose gravel and stones on the earth's surface, including what is called drift.