Achilles heel - A vulnerable spot or weakness in a person or system that could result in its failure.
A bone of contention - An issue that always causes tension and arguments.
A dead letter - An argument or law not followed by anyone.
At the eleventh hour - too late, in the last minute.
A queer fish - a strange person.
A worm's eye view - having very little knowledge about something.
At(on) the heels of - close behind or soon after something.
Apple of someone's eye - someone loved and respected deeply.
Ask for the moon - to ask for too much.
Asleep at the switch - not being alert when encountered with an opportunity.
At sixes and sevens - to be lost and bewildered.
At someone's beck and call - Always ready to serve.
At an arm's length - to keep a distance.
A red-letter day - an important day.
A nine days wonder - a pleasure for a short time.
Alma mater - Institution where one got educated.
At the drop of a hat - a willingness to do something instantly.
A cold fish - a person devoid of emotions.
A cock and bull story - an improbable excuse.
Aboveboard - straightforward, without concealment.
