tragika

Tragika is not built from tragedio. This is worth stating plainly, because Esperanto trains you to expect that an adjective beside a noun is the noun plus -a, and here it is not: tragedio and tragika are two separate borrowings that were already a pair in Greek. Zamenhof took both rather than deriving one from the other, and the same thing happened right across the -ik- family: komedio alongside komika, muziko alongside muzika, logiko alongside logika, politiko alongside politika. The -ik- in them is a fossilised Greek adjective ending, not an Esperanto suffix - you cannot take a root of your own and add -ika to it and expect to be understood.

Which leaves a small, real question: is tragedia a word? Yes, and it means something slightly different. Tragedia is of or belonging to a tragedy, the theatrical form: tragedia aktoro, an actor in tragedies. Tragika is the wider, everyday adjective for anything with the shape of a tragedy about it - an accident, a life, a decision. In practice tragika does nearly all the work and tragedia turns up only in writing about the theatre.

Temperature, against the neighbours. Malĝoja is sad, an ordinary feeling. Terura is terrible, which is about horror rather than shape. Tragika is reserved for the outcome that was both awful and, in hindsight, built into the situation: the flaw that did the damage, the death that the whole story was walking towards. Use it too freely and it wears out, exactly as it has in English. The adverb is tragike, and tragikomedio - which Esperanto builds as readily as English does - is the mixture.