A derogatory term usually applied to people who enjoy making fun of others for no real reason. Can be interpreted with multiple meanings as well.

Usually applied when a very strong come-back is required.

A Bloomer is someone with a bright outlook on life who is optimistic in nature. Bloomer's frolic in every opportunity to be happy and try to make the most out of life. The opposite of a Bloomer is a Doomer. The term Bloomer originated specifically as a counter to the Doomer on sites especially like 4Chan.