Don't stick your head out.

In Japanese grammar, 'independent words' form the main part of the sentence.

I eat boiled eggs for breakfast.

My mother scolded me.

Shh, please be quiet.

My mother scolded me.

He eats an egg every morning.

In Japanese grammar, an autonomous forms the main part of the sentence.

He was excited to try the standing position.

Ritsuo is my best friend.