Translation guide
The English word 'reflexes' refers to automatic physical reactions, quick instinctive responses, or the general concept of reflex actions. This guide helps learners express these ideas naturally in Japanese.
Describing involuntary physical reactions, such as a knee-jerk reflex or blinking.
The standard term for a physiological reflex. Used in medical and everyday contexts.
膝蓋腱反射は健康診断でよく調べられる。
The patellar reflex is often checked during physical exams.
熱いものに触れると、反射で手を引っ込める。
When you touch something hot, you pull your hand back by reflex.
Literally 'reflex nerves', often used to describe someone's quickness of reflexes, especially in sports or driving.
彼は反射神経が鋭いから、運転が上手だ。
He has sharp reflexes, so he's a good driver.
Referring to fast, almost automatic reactions in non-physical contexts, like answering quickly or dodging a question.
An adjective meaning 'reflexive' or 'instinctive', used for actions done without thinking.
彼の反射的な答えに驚いた。
I was surprised by his reflexive answer.
An adverb meaning 'instantly' or 'on the spur of the moment', often used to describe a quick, unthinking reaction.
とっさに嘘をついてしまった。
I reflexively lied. (lit. I told a lie instantly.)
Talking about reflexes as a general ability or trait, often in plural form.
Used to describe overall reflex ability. Often paired with adjectives like 鋭い (sharp) or 鈍い (dull).
年を取ると反射神経が鈍る。
As you get older, your reflexes slow down.
Can be used in a general sense, but often sounds more technical.
反射 (reflex) is the physiological reaction itself, while 反射神経 (reflex nerves) refers to the speed or quality of one's reflexes. Use 反射神経 when talking about how quick someone's reflexes are.
English often uses 'reflexes' in plural, but Japanese 反射 is usually treated as a mass noun or singular concept. Do not try to pluralize it; context makes the meaning clear.
Conditioned reflex, like Pavlov's dogs. Used in psychological contexts.
パブロフの犬の条件反射は有名だ。
Pavlov's dogs' conditioned reflex is famous.
There is training to improve your reflexes.