touchline vs sideline

touchline and sideline both are nouns.

Word	Noun	Adjective	Verb	Adverb
touchline	Yes	No	No	No
sideline	Yes	No	Yes	No

As nouns, sideline is a hypernym of touchline; that is, sideline is a word with a broader meaning than touchline:

Other hypernyms of touchline include out of bounds.

touchline (noun)	sideline (noun)
either of the sidelines in soccer or rugby	an auxiliary activity
	an auxiliary line of merchandise
	a line that marks the side boundary of a playing field

touchline (verb)	sideline (verb)
	remove from the center of activity or attention; place into an inferior position