Come by and Look on

Come by verb - To make a brief visit.

Look on and come by are semantically related In some cases you can replace term "Look on" with "Come by", this phrasal verbs are similar.

Look on verb - Observe with attention.

Come by and look on are semantically related in visit topic. Sometimes you can use "Come by" instead a verb "Look on", if it concerns topics such as visit at residence or business, be a guest of.