The most common and most likely answer to this crossword clue is the 5 letter word REGAL
I've seen this crossword clue in The Times
R
E
G
A
L
More clues leading to the result REGAL
- Majestic new composition of Elgar
- Showing great dignity knocking the beer back
- Beer from the East that's fit for a king
- Splendid beer knocked back
- Knock back beer fit for a monarch
- Brazilian cash securing good portable organ
- Brought over drink fit for a king
- Referring to girl, fit for king
- Uplifting beverage fit for the Queen
- Magnificent drink upended
Buddy explains!

The straight part
We know that "Showing great dignity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case showing great dignity = regal.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 REGAL mean?
REGAL adjective- Of or relating to royalty.
- Befitting a king, queen, emperor, or empress.
- A small, portable organ whose sound is produced by beating reeds without amplifying resonators. Its tone is keen and rich in harmonics. The regal was common in the sixteenth and seventeenth centuries; today it has been revived for the performance of music from those times.
- An organ stop of the reed family, furnished with a normal beating reed, but whose resonator is a fraction of its natural length. In the sixteenth and seventeenth centuries these stops took a multitude of forms. Today only one survives that is of universal currency, the so-called Vox Humana.