Middle English: from Old Norse líkr; related to alike
The use of like as a conjunction meaning ‘as’ or ‘as if’ (I don’t have a wealthy set of in-laws like you do; they sit up like they’re begging for food) is considered by many to be incorrect. Although like has been used as a conjunction in this way since the 15th century by many respected writers, it is still frowned upon and considered unacceptable in formal English. In more precise use, like is a preposition, used before nouns and pronouns: to fly like a bird; a town like ours. See also go1 (usage).