Translation guide
The English word 'prone' has two main uses: describing a physical position (lying face down) and describing a tendency or likelihood (prone to something). This guide covers both.
Describing a person or body positioned with the front or face downward.
The most common and natural way to say 'lying face down' or 'prone position'. Used as a noun or with する to mean 'lie on one's stomach'.
Verb phrase meaning 'to lie face down' or 'to get into a prone position'.
マッサージの間、うつ伏せになってください。
Please lie face down during the massage.
Literally 'crawling on the belly', often used for babies or in descriptive contexts. Slightly more literary or technical than うつ伏せ.
Describing someone or something that is likely to experience something negative or has a natural inclination.
Attach to the verb stem to mean 'prone to doing' or 'easily does'. Very common and natural for tendencies, especially negative ones.
彼は風邪をひきやすい。
He is prone to catching colds.
この機械は故障しやすい。
This machine is prone to breaking down.
English 'prone' can mean both 'lying face down' and 'having a tendency'. In Japanese, these are completely different expressions. Use うつ伏せ for the physical position and 〜やすい/〜がち for tendencies.
Both express tendency, but 〜やすい focuses on the ease with which something happens (often due to inherent nature), while 〜がち emphasizes frequency and often carries a negative connotation. 〜やすい can be used for positive tendencies, but 〜がち is almost always negative.
赤ちゃんをうつ伏せに寝かせないでください。
Don't put the baby to sleep on its stomach.
彼はうつ伏せで本を読んでいる。
He is reading a book lying on his stomach.
赤ちゃんが腹這いで動き始めた。
The baby started moving on its belly.
Attach to verb stem or noun to mean 'tends to' or 'is prone to', often with a negative nuance. Used for recurring states or actions.
彼女は忘れっぽくて、約束を忘れがちだ。
She is forgetful and prone to forgetting appointments.
この地域は地震が起こりがちだ。
This area is prone to earthquakes.
A more formal or written expression meaning 'has a tendency to'. Used with verbs or nouns.
彼は遅刻する傾向がある。
He has a tendency to be late. / He is prone to being late.
Means 'has a (bad) tendency to'. Used for negative habits or traits, often in critical or formal contexts.
彼は物事を大げさに言うきらいがある。
He is prone to exaggerating things.
This glass breaks easily (inherent property).
最近、ガラスが割れがちだ。
Lately, glasses have been prone to breaking (frequent occurrence).
This glass breaks easily (inherent property).
最近、ガラスが割れがちだ。
Lately, glasses have been prone to breaking (frequent occurrence).