The most common and most likely answer to this crossword clue is the 10 letter word BANQUETING
I've seen this crossword clue in The Times
B
A
N
Q
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More clues leading to the result BANQUETING
Buddy explains!
The straight part
We know that "entertaining on grand scale" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case entertaining on grand scale = banqueting.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 BANQUETING mean?
BANQUETING verb- To participate in a banquet; to feast.
- To have dessert after a feast.
- To treat with a banquet or sumptuous entertainment of food; to feast.
- The act of holding or participating in a banquet.