obliquely vs sidelong

obliquely is not an adjective while sidelong is an adjective.

Word	Noun	Adjective	Verb	Adverb
obliquely	No	No	No	Yes
sidelong	No	Yes	No	Yes

As adverbs, obliquely and sidelong are synonyms defined as:

Other synonyms of obliquely include sideways.

obliquely (adjective)	sidelong (adjective)
	inclining or directed to one side
	(used especially of glances) directed to one side with or as if with doubt or suspicion or envy
	situated at or extending to the side

obliquely (adverb)	sidelong (adverb)
at an oblique angle	to, toward or at one side
to, toward or at one side	with the side toward someone or something
	on the side