have
A four letter word meaning the foundation of something is base.
Gratis is Spanish for FREE.
A four letter word meaning not kosher is: tref
-able/-ible. For example: something that is capable of being read is readable or legible.
kill
into
aver
The word pine can have that meaning.
A four-letter word for cooking fat is "lard".
A four letter word meaning to grow light as the sun rises is dawn.
The four letter word for repairing something is mend.
Writ