There're 2 words that have the stem لبى which are لبيه and لبى + a nother noun لبيه means I obey you, tell me what you want me to do. People usually say it to their parents when they call their names, or to their lovers. لبى means I'd sacrifice myself for you, or your heart . People usually say it when they see something beautiful or when they see " hot people " . It means " I like it " too. Also they add the words " heart or soul " to it. لبى قلبك - لبى روحك to express strong feelings.