The most common and most likely answer to this crossword clue is the 6 letter word REGALE
I've seen this crossword clue in The Sunday Telegraph
R
E
G
A
L
E
More clues leading to the result REGALE
- Royal couple’s last to feast
- Ply with beer, knocked back with tablet?
- Lavishly supply short man with alcoholic drink
- Royal English feast
- Wine and dine with what’s on plate and beer
- Amuse, perhaps with stories about wind
- About to have good beer as treat
- Generously provide claret, perhaps leaving Edwin with wind
- Entertain with talk about Capone being seen in Georgia
- Feast fit for a king ending with cake
Buddy explains!

The straight part
We know that "Lavishly entertain" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lavishly entertain = regale.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 REGALE mean?
REGALE noun- A feast, meal.
- To please or entertain (someone).
- To provide hospitality for (someone); to supply with abundant food and drink.
- To feast (on, with something).
- To entertain with something that delights; to gratify; to refresh.