Cwtch is Welsh word that is occasionally claimed to be untranslatable. As with most untranslatable words, it is eminently translatable.
Cwtch: noun, 1. a comforting hug; a warm embrace: 2. a cubbyhole or cupboard, or any small space for storing things safely. It is sometimes more generally translated as a 'safe space'.
Cwtch is one of those words that are convenient and common enough to sneak into English sentences when a Welsh person is speaking, seeing as it's a bit awkward to wedge a direct translation into conversation. When used in English, cwtch is almost always used to refer to a comforting hug.
Cwtch is a light anglicisation of cwtsh, itself derived from the Middle English couche, meaning a bed. In Welsh it is used as both a verb and a noun, the verb meaning, predictably, 'to hug', and less predictably, 'to croutch down'. It is generally pronounced 'crootch' (to rhyme with 'butch'), except with a Welsh accent.