sideline sideline /ˈsaɪdˌlaɪn/

noun

1. An auxiliary activity  ( avocation , by-line , pursuit , hobby , sideline , spare-time activity )
   an auxiliary activity
    Painting miniature figurines is his favorite hobby.
   Painting miniature figurines is his favorite hobby.
   
   
2. An auxiliary line of merchandise  ( sideline )
   an auxiliary line of merchandise
   
3. A line that marks the side boundary of a playing field  ( out of bounds , sideline )
   a line that marks the side boundary of a playing field
    The coach shouted instructions from the sideline during the game
   The coach shouted instructions from the sideline during the game
   
   

verb

1. Remove from the center of activity or attention; place into an inferior position  ( sideline )
   remove from the center of activity or attention; place into an inferior position
    The outspoken cabinet member was sidelined by the President
   The outspoken cabinet member was sidelined by the President