well technically speaking, some find the name "Lucifer" scary. and "leviathan" struck fear into sailors back in biblical times. other than those I really dont know of any scary words that begin with the letter "L" sorry if I was not that much of a help.
Lap is a word that begins with the letter L and rhymes with cap.
listless
love
Longjohns
logic
Latex is a 5 letter word. It begins with L and ends with X.
Love and laugh are desirable words. They begin with the letter l.
Large
ligament
Litter.
Ural
little dipper