The most common and most likely answer to this crossword clue is the 7 letter word STERNER
I've seen this crossword clue in The Times
S
T
E
R
N
E
R
More clues leading to the result STERNER
- Back Her Majesty to be more authoritarian
- Back Queen, being of greater severity
- Author’s right to be more authoritarian
- More severe back on East River
- Her Majesty seen at the back of the vessel, in a more serious mood
- Resent changes on right being more authoritarian
- More severe guide adopting force
- Pilot assumes the navy is more rigid
- More serious renters having repairs done
Buddy explains!

The straight part
We know that "more authoritarian" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case more authoritarian = sterner.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 STERNER mean?
STERNER adjective- Having a hardness and severity of nature or manner.
- Grim and forbidding in appearance.
- A director.