"Ad hoc" is an idiom that refers to something created or done on a specific occasion or for a particular purpose, without any predetermined plan or structure. It can also refer to a temporary solution or measure taken to address a problem or situation.

The idiom "blind alley" refers to a situation or path that leads nowhere or is a dead end. It can also mean a situation that appears promising at first but ultimately leads to disappointment or failure.

The idiom "riddle me" is used when someone is confused or perplexed about something. It can also be used to express disbelief or skepticism towards a statement or claim.

The idiom "all Greek to me" means that something is so difficult or unfamiliar to me that I cannot understand it or make sense of it. It is a figurative expression used to express confusion or ignorance about a particular topic.

The idiom "all the rage" means that something is very popular, fashionable, or exciting at the moment. It describes a trend, craze, or sensation that is currently gaining widespread attention and acceptance.