I don't believe there is a 3 letter word for fear in English. The closest would be 'awe' and that is not exactly the same meaning.
Trepidation.
lest
Trepidation
awe
termination
Encapsulate.
accumulated, congregated
hypothesize
accommodate
The answer is Acaulescent
enfranchise
A ten letter word for the process is metabolism. An 11 letter word is respiration.
An 11 letter word having to do with sex is fornication.
The 11-letter word that refers to a type of anime is Planimeters.
An 11 letter word that refers to invading one's property is "trespassing".
Underground is a 11 letter word starting with U and ending with D.