steal away vs slip out

steal away and slip out both are verbs.

Word	Noun	Adjective	Verb	Adverb
steal away	No	No	Yes	No
slip out	No	No	Yes	No

As verbs, steal away and slip out are synonyms defined as:

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

steal away (verb)	slip out (verb)
leave furtively and stealthily	leave furtively and stealthily