"only" means "merely" i.e. I only have a dollar[that's all the money I have] 'Just' can also be used in the same way,i.e. I just want to eat dinner!! [this is all I really want to do] "Just" is also used to refer to something that happened not too long ago. i.e. "I just ate breakfast"[not too long ago] or "Pretty Little Liars just came on!" [it came on about a few seconds ago] I'm not an expert at explaining this but I hope this cleared up confusion!