Hi, I'd say it's not common exactly, in usual speaking, but that almost all English speakers would know what it means. You can also use "caught unawares", both in places of "by surprise". For example, "I was caught unaware by the postman who knocked on the door while I was still in my dressing gown." Hope that makes sense!

Interesting! I have never heard anybody say 'caught unaware'. The word 'unaware' is an adjective, and is used with the verb 'to be' in phrases such as 'I was unaware of that fact'. The word 'unawares' is an adverb, and it describes how you were caught i.e. by surprise and unprepared for what happened. Until I read this post, I had thought that the only correct form was 'caught unawares'. You live and learn.

Hi Yi Wen, We are "caught unaware" when we are startled or unprepared for an event that happened suddenly and unexpectedly. It is really hard to say if it is a common phrase, as there are many ways to convey the same meaning. It can be commonly used although there are many alternate ways to convey the same meaning. For example, a writer can write: "I was totally unaware when he arrived." instead of writng: "I was caught unaware by his arrival." Or "I was totally unprepared when the lecturer asked me to prove the theorem," instead of writing: "I was caught unaware when the lecturer asked me to prove the theorem." I hope this helps. Cheers, Lance

You're welcome

Thanks Mikkel.