It is difficult to tell from the quality of your photo's, if you could get some better shots it will be quicker to get an ID. It could be a Guava, but that is a rough guess.
It is a pretty ambiguous sort of plant so there are a few possibilities but I'd go along with squizzy. I think it is one of the privets. Knowing your approximate location might also help to reduce the possibilities Mister Mercer. Some tropical species rarely turn up down south and vice versa.