I've come across with the sentence below:
David’s mouth is set in a grim line.
The word grin means:
- making you feel worried or unhappy
- looking or sounding very serious
- very bad, ugly, or unpleasant(informal)
But I don't understand what the phrase exactly means. Does it mean "David looks seriously"?
So, could you please expain it to me?
Note: David is an attorney.
The fuller text:
Riley hears Gwen’s scream, and despite her own immediate fear, tears up the stairs. The others are close on her heels. She arrives at the open doorway to Candice’s room.The first thing she sees is Gwen with her face buried in David’s chest, to her right, and then, beyond them, the body on the floor. [...] Riley can’t bear to look at the body anymore; she turns her attention to the others instead. Bradley is staring at Candice as if he’s seen a ghost, grabbing the edge of the desk to steady himself. David’s mouth is set in a grim line. Gwen, beside him, has her hand pressed hard against her mouth, trying not to throw up. Ian mutters, “Dear God,” and stands flat-footed, as Lauren pushes past him to the body. She moves to pull the scarf loose, touching Candice’s neck. “Get back, everyone,” David commands harshly. “There’s nothing we can do for her.”