cast
Not exactly the right description, but the closest with four letters might be seer.
The four letter word that means, "I forbid," is veto.veto
The four letter word is dawn.
A four letter word meaning the foundation of something is base.
Exit
The word is scam.
Rend is a four letter word that means to tear into pieces. Tear is also a four letter word meaning to pull apart.
aide
Fast
step
asea
Talk.