check out vs sound out

check out and sound out both are verbs.

Word	Noun	Adjective	Verb	Adverb
check out	No	No	Yes	No
sound out	No	No	Yes	No

As verbs, check out and sound out are synonyms defined as:

Other synonyms of check out include feel out.

check out (verb)	sound out (verb)
examine so as to determine accuracy, quality, or condition	try to learn someone's opinions and intentions
announce one's departure from a hotel	speak, pronounce, or utter in a certain way
try to learn someone's opinions and intentions
record, add up, and receive payment for items purchased
withdraw money by writing a check
trace
be verified or confirmed; pass inspection