definition of
sideline

[1] #1 sideline n. [out of bounds] a line that marks the side boundary of a playing field. wn

[2] #2 sideline v. remove from the center of activity or attention; place into an inferior position; "The outspoken cabinet member was sidelined by the President". wn

[3] #3 sideline n. an auxiliary line of merchandise. wn

[4] #4 sideline n. [avocation, by-line, hobby, pursuit, spare-time activity] an auxiliary activity. wn