The four letter word that means, "I forbid," is veto.
veto
Forbid, prohibit, ban, abjure are four words that mean "to command not to do something."
Bar
The four letter word is dawn.
Exit
A four letter word meaning the foundation of something is base.
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.
Ban
A six letter word to command not to do something is to forbid.
aide
Fast
asea