The most common and most likely answer to this crossword clue is the 10 letter word SALTCELLAR
I've seen this crossword clue in The Daily Telegraph
S
A
L
T
C
E
L
L
A
R
Buddy explains!

The straight part
We know that "Seasonal dispenser of wit at table?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case seasonal dispenser of wit at table? = saltcellar.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 SALTCELLAR mean?
SALTCELLAR noun- A small open container holding salt for use in the kitchen or on a dining table
- A salt shaker, a closed container with perforated lid for sprinkling salt