Eucaryote and Prokaryote

Eucaryote noun - An organism with cells characteristic of all life forms except primitive microorganisms such as bacteria; i.e. an organism with `good' or membrane-bound nuclei in its cells.

Prokaryote is an antonym for eucaryote.

Prokaryote noun - A unicellular organism having cells lacking membrane-bound nuclei; bacteria are the prime example but also included are blue-green algae and actinomycetes and mycoplasma.

Eucaryote is an antonym for prokaryote.