Sometimes it depends on what type of dictionary it is.
Some antonyms for heartily include: gravely, indifferently.
Antonyms for "modern" could include traditional, outdated, or old-fashioned. Antonyms for "fresh" could include stale, old, or rotten.
Antonyms for gallantry include cowardice. Synonyms for gallantry include bravery and heroism.
Antonyms of "Paradox" include "Plausible", "Possible", "Feasible", and "Thesis".
Antonyms of theory include fact, reality, evidence, and truth.
Antonyms for raconteur would include "truth-teller" or "straight shooter."
Antonyms for ill include healthy, robust, well (as in, 'I am well') and recovering.
Antonyms of "merge" are separate, divide, or disconnect. Synonyms for "separate" include divide, detach, or segregate.
Antonyms of kindle would include: douse, extinguish, quench and turn off.
Antonyms for parry include, but are not limited to: meet, face, encounter, confront, allow, and attract.
There do not appear to be any direct antonyms for the word 'wiseacre'. A synonym for wiseacre is arrogant, and the antonyms for this word include humble, modest and meek.
There is no antonym for coal. There usually are not antonyms for physical objects.