The phrase "smile up on" is an idiomatic expression that means to smile at someone or something. There are various synonymous phrases that can be used instead of this phrase. Some of these include "smile down upon," "smile upon," "beam upon," "grin at," "smirk at," "flash a smile at," "give a smile to," "direct a smile at," and "bestow a smile upon." Each of these phrases can be used in different contexts, depending on the intention behind the smile. Whether it is to express happiness, friendliness, appreciation, or any other emotion, there is always a synonym for "smile up on".