spare-time activity vs avocation

spare-time activity and avocation both are nouns.

Word	Noun	Adjective	Verb	Adverb
spare-time activity	Yes	No	No	No
avocation	Yes	No	No	No

As nouns, spare-time activity and avocation are synonyms defined as:

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

spare-time activity (noun)	avocation (noun)
an auxiliary activity	an auxiliary activity