It can mean either you didn't pay enough attention, or you just didn't understand.
Basically, it means that you're hearing what the other person is saying, but you're not actually listening and taking in what they're saying to you. This is the real answer: Not listening to what is being said. Not attentive.
This is not an idiom. When you compare two things by saying one is the other, it is a metaphor. It means that however you keep your house reflects your personality, and vice versa.
Peter's mother suggested that he should save his pocket money up for a bicycle, but her advice went in one ear and out of the other and he spent it all on sweets. Here's another one: Ryan's mother suggested that he should save his pocket money up for a bicycle, but her advice went in one ear and out the other and he spent it all on pokemon cards.
The idiom "ear to the ground" means to pay close attention in order to gather information and stay informed about a situation or upcoming event. It signifies being vigilant and aware of one's surroundings.
It emphasizes uniqueness.
"A penny" isn't an idiom - it's just a one-cent American coin.
Eternal isn't an idiom. It's a word. Idioms are phrases that seem to mean one thing but mean something else.
This isn't an idiom. Telling a story means to speak and relay a tale - which can be a true one or a false one.
it means to control someone
It means to raise one eyebrow.
This is an idiom meaning to narrow your focus down. It can also mean to narrow your aim and focus on one thing to hit. Picture the zero as a target and you get the idea of the idiom.
This is not an idiom. Some people call their loved one by a pet name like "honey" or "darling" or "sweetie."