The most common and most likely answer to this crossword clue is the 9 letter word EMPRESSES
I've seen this crossword clue in The Daily Telegraph
E
M
P
R
E
S
S
E
S
More clues leading to the result EMPRESSES
Buddy explains!
The straight part
We know that "Some heads of state" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case some heads of state = empresses.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 EMPRESSES mean?
EMPRESSES noun- The female monarch (ruler) of an empire.
- The wife or widow of an emperor or equated ruler.
- The third trump or major arcana card of most tarot decks.
- A female chimpanzee.
- A deciduous tree, Paulownia tomentosa
- To affect (someone) strongly and often favourably.
- To make an impression, to be impressive.
- To produce a vivid impression of (something).
- To mark or stamp (something) using pressure.
- To produce (a mark, stamp, image, etc.); to imprint (a mark or figure upon something).
- To fix deeply in the mind; to present forcibly to the attention, etc.; to imprint; to inculcate.
- To compel (someone) to serve in a military force.
- To seize or confiscate (property) by force.