endorsement vs secondment

endorsement and secondment both are nouns.

Word	Noun	Adjective	Verb	Adverb
endorsement	Yes	No	No	No
secondment	Yes	No	No	No

As nouns, endorsement and secondment are synonyms defined as:

Other synonyms of endorsement include indorsement, second.

endorsement (noun)	secondment (noun)
the act of endorsing	the detachment of a person from their regular organization for temporary assignment elsewhere
formal and explicit approval	a speech seconding a motion
a promotional statement (as found on the dust jackets of books)
a speech seconding a motion
a signature that validates something