Diamond heads for royal head of monarch — belatedly (5)

I believe the answer is:

rhomb

'diamond' is the definition.
(I know that diamond can be written as rhomb)

'heads for royal head of monarch belatedly' is the wordplay.
'heads for' indicates taking the first letters.
The first letters of 'royal head of monarch belatedly' is 'RHOMB'.

(Other definitions for rhomb that I've seen before include "Figure on plane" , "Equilateral parallelogram" , "Quadrilateral with four equal sides" , "Crystal with six faces having parallel edges" , "Crystal shape" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.