idle
lazy
'Lazy' might fit, also 'foul', or 'icky'.
The 4-letter root word meaning against or opposite is "anti."
Oh, dude, that's easy peasy. The word you're looking for is "show." Like, you know, when you want to display something to the world but you're too lazy to say a longer word. So, yeah, "show" is your go-to 4-letter exhibitionist word.
pass
care
Dues
gnus
Guts
left
Loon.
Able