No 4 letter words but:
VDU
Monitor
Display
All mean computer screen.
A four letter word meaning not kosher is: tref
box, computer screen, a TV, and waffles
Wind (screen or shield)
kill
aver
into
The word pine can have that meaning.
A four-letter word for cooking fat is "lard".
user
A four letter word meaning to grow light as the sun rises is dawn.
quiz exam
stop or halt is a four letter word meaning the opposite of go.