A "fly chaser" is someone who is obsessed with chasing after flies. There are several synonyms for this term that can be used depending on the context. One of the most common synonyms is "fly swatter." This term is used to describe someone who uses a tool to kill flies, such as a fly swatter or a fly zapper. Another term that can be used is "fly catcher," which refers to someone who captures flies in a trap or with their hands. A more poetic synonym for "fly chaser" is "fly hunter," which conjures up images of a skilled hunter tracking down their prey. Other related synonyms include "bug enthusiast" and "insect lover".