To go, to travel.  
Example: ég fór út um allt (I travelled everywhere), þetta fór út um þúfur (It went down the drain), þetta fer í taugarnar á mér (this goes on my nerves). 

To leave, to depart 
This is actually just an extension of the other meaning, with the additional meaning of "away". Example: Ég er að fara (I´m leaving), lestin fer klukkan tvö en kemur aftur klukkan þrjú (the train leaves at two but comes back at three). 

NOTE: What is most important for what follows regarding the middle voice is that this meaning is intransitive (has no object).  You can not go anyone.  Even though in the second meaning where the meaning is to go "away", it does not mean leaving anything in particular.  Its meaning indicates only direction (as in "going away") without hinting at something being left. So, in Icelandic, when you leave, you just leave without leaving anything in particular.  For the more courteous departure you would use another verb. 

REFLEXIVE: Farast therefore does not mean anything reflexive.  The meaning of the verb simply cannot be turned back on the agent because it already indicates effect on the agent.  You cannot go yourself.  You just go. 

RECIPROCAL: Farast does not mean anything reciprocal either.  Intransitive verbs cannot have an object, let alone a reciprocal object.  You cannot go yourself, much less each other. 

PASSIVE: Farast is possibly passive.  If we imagine "fara" to be active, then "farast" can mean an involuntary going away, sudden departure, such as death.  And that is what it means.  It means to die accidentally, depart.  The verb does not apply to suicides, only accidental sudden deaths (and for death due to old age is "andast").  The generic term for "dying" is "deyja" but this has a narrower meaning of premature accidental death as indicated by its passive -st. 

INCHOATIVE: Farast has nothing to do with inchoative meanings.  It is not a development into a state of being filled withs "för" (tracks).  One might humorously say so about a pristine soil run over by a car, thus leaving marks on it.  Thus: Farast (to be covered with tracks) is technically possible. 

thus: