noun

• (countable, obsolete) A spark.
  ""[...] That's none such an entirely bad little man, yon little man with the red head," said Alan. "He has some spunks of decency.""
• (uncountable) Touchwood; tinder.
  "Spunk, or Touch-wood prepared, might perhaps make it Russet: and some, as Beringuccio affirmeth, have promised to make it Red."
• (countable, chiefly Scotland, obsolete) A piece of tinder, sometimes impregnated with sulphur; a match.
  "At present, her only means of procuring subsistence for herself and children, is by making spunks or matches, which, either she or her eldest child, a girl about six years of age, sells from door to door."
• (uncountable) Courage; spirit; mettle; determination.
  "1847, Anne Brontë, Agnes Grey, ch 17. She showed me the letters of another individual, too, the unfortunate Mr. Green, who had not the courage, or, as she expressed it, the “spunk,” to plead his cause in person, but whom one denial would not satisfy: he must write again and again."

verb

• (intransitive, obsolete) To catch fire; flame up.
• (intransitive, slang, vulgar) To ejaculate.
  "He spunked into the condom."
• (transitive, slang, vulgar) To waste (money etc.).