The words rain, train, crane, drain, and grain rhyme with brain.
There is no word that rhymes with slither and means fast. The closest word is hither, which means come here. The rest are not related to movement directly at all.
throw
cuff
board
The word "crappy" doesn't exactly match the meaning of mad but can be used to convey someone's mood. Most importantly, it rhymes.
trake
mane smart one
Brain dead Easily led Thoughts/brain like lead Not sure when you posted this... hope it's still relevant
The word that means and rhymes with cloak is "joke."
The word that means kneel and rhymes with melt is "knelt."
The word "afraid" slant rhymes with the word "away" but means scared.
Vain ,
That would be "Dane".
pain
The word that rhymes with day and means sky is "gray."
The word that rhymes with angel and means free is "mangel."
The word that rhymes with "creed" and means the opposite of follow is "lead".