sideline vs avocation

sideline and avocation both are nouns.

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

As nouns, sideline and avocation are synonyms defined as:

Other synonyms of sideline include by-line, hobby, pursuit, spare-time activity.

sideline (noun)	avocation (noun)
an auxiliary activity	an auxiliary activity
an auxiliary line of merchandise
a line that marks the side boundary of a playing field

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