slip away vs sneak away

slip away and sneak away both are verbs.

Word	Noun	Adjective	Verb	Adverb
slip away	No	No	Yes	No
sneak away	No	No	Yes	No

As verbs, slip away and sneak away are synonyms defined as:

Other synonyms of slip away include slip out, sneak off, sneak out, steal away.

slip away (verb)	sneak away (verb)
for time to move forward	leave furtively and stealthily
leave furtively and stealthily