yell at (someone or something)
1. To address someone or something with a loud cry or shout. Don't you dare yell at my children that way! He stood in the field yelling at the night sky for all of his misfortunes.
2. To express something to someone or something with a loud cry or shout. In this usage, a noun or pronoun is used between "yell" and "at." I had to yell my instructions at the engineers below me due to the high winds. The coach kept yelling obscenities at the referees during the game.
yell something at someone or something
to shout something at someone or something, usually in anger. Please don't yell those things at me. He stood on the porch, yelling curses at a dog on his lawn.
yell at someone or something
to shout at someone or something, usually in anger. Please don't yell at me. There is no point in yelling at a cat.
To shout at someone or something in anger, often at length: The coach yelled at the team after they lost the game.