examiner vs tester

examiner and tester both are nouns.

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

As nouns, examiner and tester are synonyms defined as:

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

Other synonyms of examiner include quizzer.

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