The idiom "bona fide" means something that is genuine, true, or valid. It is often used to describe a document, contract, or other legal documents that are meant to be authentic and not forged.

The idiom "in dire straits" means to be in a very difficult or precarious situation that requires immediate attention or action. It can also mean being in an extremely challenging position where one may need help or support from others.

The idiom "between you and me" is used to refer to a secret or confidential matter that should only be known between two people. It implies that there is an agreement between the two parties involved that they will not share this information with anyone else.

The idiom "when hell freezes over" is used to describe a situation that is highly unlikely to occur. It is often used as an expression of disbelief or skepticism when someone makes a statement that seems unrealistic.

The idiom "spine-tingling" is used to describe a feeling of excitement, nervousness, or fear that makes one's spine tingle. It can also refer to a sudden chill or goosebumps.