expression, ichidan verb
run out of oil; need lubrication
Literal meaning: a machine or mechanism loses its lubricating oil, causing friction or malfunction.
自転車のチェーンは油が切れると音がうるさくなる。
When the bicycle chain runs out of oil, it gets noisy.
expression, ichidan verb
run out of energy; lose steam
Idiomatic use: a person's motivation, stamina, or momentum runs out, like a machine without oil.
彼は途中で油が切れて、仕事を最後までやり遂げられなかった。
He ran out of steam halfway and couldn't finish the job.