sight-sing vs sightsing

sight-sing and sightsing both are verbs.

Word	Noun	Adjective	Verb	Adverb
sight-sing	No	No	Yes	No
sightsing	No	No	Yes	No

As verbs, sight-sing and sightsing are synonyms defined as:

sight-sing and sightsing: sing from a score without having seen it before

sight-sing (verb)	sightsing (verb)
sing from a score without having seen it before	sing from a score without having seen it before