Serious accent (5)

I believe the answer is:

grave

This clue is a double definition.

'serious' is the first definition.
(both can mean solemn)

'accent' is the second definition.
(I know that grave is a type of accent)

(Other definitions for grave that I've seen before include "Hazardous" , "of importance" , "In which to lay a corpse" , "Sombre in the sepulchre" , "Solemn - burial place" .)

I've seen this clue in The Irish Independent.

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