The most common and most likely answer to this crossword clue is the 6 letter word RIFFLE
I've seen this crossword clue in The Times
R
I
F
F
L
E
Buddy explains!
The straight part
We know that "activity at card table?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case activity at card table? = riffle.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 RIFFLE mean?
RIFFLE noun- A swift, shallow part of a stream causing broken water.
- A succession of small waves.
- A trough or sluice having cleats, grooves, or steps across the bottom for holding quicksilver and catching particles of gold when auriferous earth is washed. Also one of the cleats, grooves or steps in such trough.
- A quick skim through the pages of a book.
- The act of shuffling cards; the sound made while shuffling cards.
- To flow over a swift, shallow part of a stream.
- To ruffle with a rippling action.
- To skim or flick through the pages of a book.
- To leaf through rapidly.
- To shuffle playing cards by separating the deck in two and sliding the thumbs along the edges of the cards to mix the two parts.
- To idly manipulate objects with the fingers.
- To prepare samples of material using a riffler.
- In seal engraving, a small metal disc at the end of a tool.