thief in the night

== English == === Etymology === A calque from Ancient Greek κλέπτης ἐν νυκτί (kléptēs en nuktí). === Pronunciation === IPA(key): /θiːf ɪn ðə naɪt/ === Noun === thief in the night (plural thieves in the night) Something stealthy or that occurs without warning. ==== Usage notes ==== Mostly used in similes, after like.