Affirmative. Originally used over the radio to signify that you heard the other - you guessed it - 'loud and clear', the term now simply means "Yes, I understand you, now kindly leave me alone."
Teacher: "By Lord Iain, I want that damned work in tomorrow or it's your head! Do you hear me?"
Iain: "Loud and clear."
Talking loud and clear
Saying just what I feel
Lying in the grass
With the sun on our backs
It doesn't really matter
What we do or what we say
With every little movement
We give ourselves away
Opposite and opposite
Decisions are reversed
Facing one another
With words that couldn't hurt
With every little word
You're getting closer to me
Talking loud and clear
Saying just what we feel today
Talking loud and clear
Saying just what we feel
Lying in the grass
We've got time on our hands
Body next to body
With silence all around
We understand each other
But didn't make a sound
Promises and promises
Of vows we shall return
Facing one another
I thought my heart would burn
You turn to move away
But then get closer to me
Talking loud and clear
Saying just what we feel today
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"