Definition from Wiktionary, the free dictionary
polecat (plural polecats)
- A weasel-like animal of the genus Mustela, notably the European polecat, Mustela putorius.
- (US, dialect) A skunk.
- 1919, Ronald Firbank, Valmouth, Duckworth, hardback edition, page 61
- By the little garden pergola open to the winds some fluttered peacocks were blotted nervelessly amid the dripping trees, their heads sunk back beneath their wings: while in the pergoda itself, like a fallen storm-cloud, lolled a negress, her levelled, polecat eyes semi-veiled by the nebulous alchemy of the rainbow.
Derived terms 
skunk — see skunk