steal away vs slip away

steal away and slip away both are verbs.

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

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

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

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