The most common and most likely answer to this crossword clue is the 8 letter word SPANKING
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More clues leading to the result SPANKING
Buddy explains!

The straight part
We know that "Vigorous/act of corporal punishment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vigorous/act of corporal punishment = spanking.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPANKING mean?
SPANKING verb- To beat, smack or slap a person's buttocks, with the bare hand or other object, as punishment, gesture, or form of sexual interaction.
- To soundly defeat, to trounce.
- To hit very hard
- To move rapidly.
- A form of physical punishment in which a beating is applied to the buttocks.
- An incident of such punishment, or such physical act in a non-punitive context, such as a birthday spanking.
- Fast and energetic.
- Brisk and fresh.
- (now usually with “new”) An intensifier.