lieu vs behalf

lieu and behalf both are nouns.

Word	Noun	Adjective	Verb	Adverb
lieu	Yes	No	No	No
behalf	Yes	No	No	No

As nouns, behalf is a hyponym of lieu; that is, behalf is a word with a more specific, narrower meaning than lieu:

lieu: the post or function properly or customarily occupied or served by another
behalf: as the agent of or on someone's part (usually expressed as `on behalf of' rather than `in behalf of')

lieu (noun)	behalf (noun)
the post or function properly or customarily occupied or served by another	as the agent of or on someone's part (usually expressed as `on behalf of' rather than `in behalf of')
	for someone's benefit (usually expressed as `in behalf' rather than `on behalf' and usually with a possessive)