Translation guide
The most common and natural way to say 'scientist' in Japanese is 科学者 (かがくしゃ). This is a broad term covering researchers in natural and social sciences. In academic or professional contexts, 研究者 (けんきゅうしゃ) 'researcher' is often used, especially when emphasizing the act of research rather than the title. For specific fields, compound words like 物理学者 (ぶつりがくしゃ) 'physicist' are common.
scientist (general)
To refer to a person who works in science in a general sense.
The standard translation for 'scientist'. It is neutral and widely understood. Use this when you mean a scientist in general, without specifying the field.
He is a famous scientist.
Means 'researcher'. Often used interchangeably with 科学者 in contexts where the person is actively conducting research. It can sound more academic and is common in university or lab settings.
To specify the scientific discipline, e.g., physicist, chemist, biologist.
The suffix 学者 (がくしゃ) attaches to a field of study to mean 'scholar of ~' or 'scientist in ~'. For example, 物理学 (physics) + 学者 = 物理学者 (physicist). This is the most common way to form field-specific scientist terms.
To refer to a scientist in social sciences like economics, sociology, etc.
The same pattern applies to social sciences. For example, 経済学者 (economist), 社会学者 (sociologist). Note that 科学者 is sometimes perceived as more natural science-oriented, so using the specific term is safer.
To emphasize the act of researching rather than the title 'scientist'.
科学者 (かがくしゃ) specifically means 'scientist' and is associated with the natural sciences. 研究者 (けんきゅうしゃ) means 'researcher' and can be used for any field, including humanities and social sciences. In many contexts they overlap, but 研究者 emphasizes the act of research, while 科学者 emphasizes the profession of science.
When possible, use the specific field + 学者 (がくしゃ) to sound more natural and precise. For example, say 物理学者 (physicist) instead of 科学者 if you know the field.
She wants to become a scientist.
Becoming a scientist requires effort.
She works as a researcher at a university.
He is a physicist.
That chemist discovered a new element.
Even when the field is known, 科学者 can be used if the context makes the field clear, but it is less precise.
He is a scientist at NASA.
She is an economist.
Literally 'social scientist'. This word exists but is less common than the specific field term. It might be used in formal contexts.
Debate continues among social scientists.
When the focus is on the person's role as a researcher, 研究者 is more natural. It is used for both scientific and non-scientific research (e.g., humanities).
He is a cancer researcher.
The researchers developed a new treatment.
科学者たちは新しい惑星を発見しました。
Scientists have discovered a new planet.