gastama

Three pieces, and none of them is an affix. Gasto is a guest, am- is the root of ami, to love, and -a makes an adjective. Guest-loving: hospitable. It is a compound, not a derivation, and the difference matters because -am- is not on the official list of Esperanto suffixes at all. You are welding two ordinary roots together, exactly as piedpilko welds foot and ball.

The pattern is productive and worth stealing. Pacama is peace-loving, homama is philanthropic, laborama means loving one's work, mokama is fond of mocking. Once you see -ama as "loves doing this", a whole shelf of adjectives opens up.

Now the contrast that actually earns its keep: -ama against -ema.-Em- is an official suffix, and it means inclined or prone to, with no affection in it. So laborema is industrious, disposed to work, whether or not the person enjoys it; laborama says they love the work. Kolerema is irritable, quick to anger; nobody would say kolerama, because loving anger is a different claim. The rough test: -ema describes a tendency, -ama describes a taste. And gastema would mean inclined to have guests, which is close enough that you will meet it, but gastama is the standard word.

Where you meet it in the wild. Esperanto's Pasporta Servo, the list of speakers who put visiting Esperantists up for nothing, runs entirely on this adjective, and gastama is the compliment the movement pays most often. The noun is gastamo, hospitality, and the place is a gastejo. More on the spoken, travelling side of the language in spoken Esperanto.