Very similar to a "Creeper". A Lerper's intentions are to simply receive human contact, verbally, visually, or physically. A Lerper has no real desire for sex specifically, but rather they solely are interested in relieving the enormous state of loneliness they exist in. (Verb: Lerp Adj.: Lerpish)
"So when Allison was at the mall, she totally got creeped out by this lerper"
"Dude, Eric was totally lerping on that chick!"
"Mike was acting all lerpish today with Jen..."
A person high on crystal meth who will steal something from you and then help you look for it.
Someone scoping out the premises looking for things to cluck (steal)
AKA - Theif
Bottom of the barrel sucker fish
"Dont leave that lerper alone with anything of value"
"That guy was lerping around the neighborhood"