retainer vs servant

retainer and servant both are nouns.

Word	Noun	Adjective	Verb	Adverb
retainer	Yes	No	No	No
servant	Yes	No	No	No

As nouns, retainer and servant are synonyms defined as:

retainer and servant: a person working in the service of another (especially in the household)

retainer (noun)	servant (noun)
a dental appliance that holds teeth (or a prosthesis) in position after orthodontic treatment	a person working in the service of another (especially in the household)
a person working in the service of another (especially in the household)	in a subordinate position
a fee charged in advance to retain the services of someone