lmgtfy = (abbreviation) let me google that for you
www.lmgtfy.com lets you google for someone else. So for example, instead of answering a question, you get to be a smartass and answer it through Google!
Oft used texting expression employed by sms fanbois. lmgtfy grandma since you're still using legacy-sms for texting. Smart phones can engage legacy-sms via SIP, xmpp, and email.
LMGTFY, or Let me google that for you, is a commerical slang. Can be used for informal (a.k.a less boring english) things too.
CO-WORKER: I need help typing "how to literally make your girl fuck you so you idiotboys don't have to"
ME: Can you LMGTFY?
CO-WORKER: Sure. I will make ya VIP and your girl will like it to 👍