(n.) One who assays. Specifically: One who examines metallic ores or compounds, for the purpose of determining the amount of any particular metal in the same, especially of gold or silver.

analyzer assayer behavior therapist clinical psychologist essayer examiner experimenter headshrinker hypnotherapist narcotherapist psychiatrist psychoanalyst psychoanalyzer psychotherapeutist psychotherapist research worker researcher shrink shrinker test driver test pilot tester tryer-out