locum tenens vs locum

locum tenens and locum both are nouns.

Word	Noun	Adjective	Verb	Adverb
locum tenens	Yes	No	No	No
locum	Yes	No	No	No

As nouns, locum tenens and locum are synonyms defined as:

locum tenens and locum: someone (physician or clergyman) who substitutes temporarily for another member of the same profession

locum tenens (noun)	locum (noun)
someone (physician or clergyman) who substitutes temporarily for another member of the same profession	someone (physician or clergyman) who substitutes temporarily for another member of the same profession