None. The sound of 'x' in Hebrew isn't written with one letter like in English, but with two, like 'ks'; besides, most of the words with an 'x' sound in our language are taken from English or other langs and not being original.
The double consonant word that begins with the letter x is "excess."
There is not a word
x-ray
xenophobiaxylophoneXanaduXanaxXebecXenolithXenonXenophobiaXeroxXhosaXylemXylographyXyloid
x like an x ray
Xenophobia.
booby cat
Unfix is a 5 letter word. It begins with U and ends with X.
x-raying
· x-ray · Xerox · xylophone
Latex is a 5 letter word. It begins with L and ends with X.
The word x-ray is a common compound noun. The word Xbox is a proper compound noun.