tester vs examiner

tester and examiner both are nouns.

Word	Noun	Adjective	Verb	Adverb
tester	Yes	No	No	No
examiner	Yes	No	No	No

As nouns, tester and examiner are synonyms defined as:

tester and examiner: someone who administers a test to determine your qualifications

Other synonyms of tester include quizzer.

tester (noun)	examiner (noun)
a flat canopy (especially one over a four-poster bed)	an investigator who observes carefully
someone who administers a test to determine your qualifications	someone who administers a test to determine your qualifications