Both vodka and whisky come from words for "water". Coincidence? A poetic drunkenly-inspired coinage made far back in the mists of time?
Vodka is borrowed from Russian водка which is from вода "water". -ка is a diminutive suffix, so vodka etymologically means "little water". It's from Proto-Indo-European *wed- "water, wet".
Whisky was borrowed from Scots Gaelic uisge beatha and/or Irish Gaelic uisce beatha, meaning "water of life". (In my older post I say Scots Gaelic, but the OED doesn't seem sure.) It was also spelled usquebaugh and whiskybae, until the last syllable was dropped. Irish Gaelic uisce "water" is from *ud-skio-, a suffixed zero-grade form of *wed-.
Other unrelated words with the same sense are aquavitae from the Latin for "water of life", and French eau-de-vie meaning "brandy".
In English, *wed- became water, wet and wash.