alternate in WordNet English dictionary

1. someone who takes the place of another person
   surrogate  alternate  replacement 
   

1. do something in turns
   "We take turns on the night shift"
   alternate  take turns 
   
2. go back and forth; swing back and forth between two states or conditions
   alternate  jump 
   
3. reverse (a direction, attitude, or course of action)
   interchange  tack  switch  alternate  flip  flip-flop 
   
4. be an understudy or alternate for a role
   understudy  alternate 
   
5. exchange people temporarily to fulfill certain jobs and functions
   alternate 
   

1. of leaves and branches etc; first on one side and then on the other in two ranks along an axis; not paired
   "stems with alternate leaves"
   alternate 
   
2. serving or used in place of another
   "an alternative plan"
   alternate  alternative  substitute 
   
3. occurring by turns; first one and then the other
   "alternating feelings of love and hate"
   alternate  alternating 
   
4. every second one of a series
   "the cleaning lady comes on alternate Wednesdays"; "jam every other day"- the White Queen
   alternate