The most common and most likely answer to this crossword clue is the 6 letter word KAISER
I've seen this crossword clue in Financial Times
K
A
I
S
E
R
More clues leading to the result KAISER
- Emperor’s spirit lives on in retirement
- Half-heartedly mouth entertaining answer for emperor
- German emperor in King Arthur’s capital is seen by Her Majesty
- Ruler over empire, King is embracing a Queen
- Leader is between king and a queen
- King after king inheriting first-class/special title
- King lives with queen, hosting a ruler
- ‘Sovereign Bakeries’ failing, remain closed down
- Emperor, okay at heart, lives on in retirement
Buddy explains!
The straight part
We know that "ruler" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ruler = kaiser.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 KAISER mean?
KAISER noun- An emperor of a German-speaking country, particularly the Holy Roman Empire (962–1806), the Austrian Empire (1806–1918), or the German Empire (1871–1918) — often specifically Wilhelm II — or any emperor.
- A Kaiser roll.
- A person who exercises or tries to exercise absolute authority; autocrat.