Lachwen. I was so proud of this...
Lach (or, technically,
lhach) means "leaping flame" in Sindarin. "
Wen, of course, is "maiden." So
Lachwen, the Maiden of Leaping Flame.
I made up this name partially because I love fire, partially because of my own firey temper, but in reality it was a surname for a character in a fanfic I never finished. She was sort of an Elven version of Éowyn, you know, a hardcore warrior-maiden who travelled with the Rangers. In my story, Elrohir gave her the name after seeing her first fight against Orcs, when she seriously poned them.
In a startling coincidence, the character's given name was Esgalost, "The Hidden Fortress," which was just what I got from the name generator. But I can help you with your name, Esgallhugwen!
OK, the element you don't understand is not
hug but
lhug (notice the double L in your name?).
Lhûg is the Sindarin form of Quenya
(h)lókë, which means "snake, serpent." The derivative
lok-, "bend, loop", is found in
Urulóki, the Quenya name for Dragons. So your name means something like "Hidden Serpent Maiden."
Wow, I've read The Silmarillion a few too many times...