A word beginning with R for sleep is rest.
sleep
This could be dysfunctional, disadvantageous, disposable, dispensable, defunct, discarded, doomed, dead.
There are none. However, "ax" can be considered a synonym of sword, and the second letter is an x. There is also "excalibur."
Another word for a plank of wood that begins with the letter "b" is "board." A board typically refers to a flat, thin piece of wood that can be used in construction or various projects.
move
Haughty is another word for arrogant that begins with the letter H.
Another word for registered voters that begins with the letter C is constituents.
Unusual is another word for interesting.
atrocious
annoying
Isle
A four letter word for poverty is need.
strenutation
Comradehip is another word for friendship.
eager
one is advocateannounce
Amused Amazed