WordNet records no synonym and no antonym for klondike. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a region in northwestern Canada where gold was discovered in 1896 but exhausted by 1910
a form of solitaire that begins with seven piles of cards with the top cards facing up; descending sequences of cards of alternating colors are built on these piles; as aces become available they are placed above the seven piles; the object is to build sequences in suit from ace to king as the remaining cards are dealt out one at a time
Synonyms, antonyms and the broader and narrower relations for klondike come from Princeton University’s WordNet. Full sources and licences.