Illegible.
7
Yes, indestructible is a word. It means incapable of being destroyed.
Terminal
unalienable
One possible substitute for "their" is "his" or "her" depending on the gender of the person/people being referred to. Another substitute can be "its" when referring to a non-human object or entity.
The opposite of the word capable is incapable.
my best guess is permanent
The word incompetent means the lacking of qualification or being incapable, inadequate, unable or unsuitable. It is the opposite of the term competent.
in- is the prefix of incapable. Uncapable is not an actual word and it can be mistaken for incapable.
indescribableIneffable. -adjective 1. incapable of being expressed or described in words; inexpressible: ineffable joy.
He was incapable of performing even the most trivial task.
Audible."inaudible" quite literally means "incapable of being heard"; by stripping the prefix "in-", you get the word "audible", which indeed means "capable of being heard".
The word is cohabitation.