Xenon
Xylophone
Xenophobia
X-ray
A four letter word beginning with C and ending with X is crux.
There is no synonym for awesome beginning with the letter x.
x-ray
Coxa
use a dictionary
Xenophobic
a four letter word beginning with X is xebec (a small historical three masted sailing ship with square sails.
Five letter words starting with C and ending with X are calyx and codex.
Xiv, xed, xii.
As. The shortest word beginning with the letter a is "a"
Calyx, codex and cylix are 5 letter words. They begin with c and end with x.
The most common word of that form is "relax". Others are "radix" and "redux".