listen to the pronunciation of tight-lipped
Englisch - Englisch
Unwilling to divulge information
Having the lips pressed together

He would have sprung upon Captain Blood, who stood aloof, alert, tight-lipped, and watchful.

Someone who is tight-lipped has their lips pressed tightly together, especially because they are angry or disapproving. He was sitting at the other end of the table, tight-lipped and angry
If you describe someone as tight-lipped, you mean that they are unwilling to give any information about something. Military officials are still tight-lipped about when or whether their forces will launch a ground offensive. forthcoming
inclined to secrecy or reticence about divulging information; "although they knew her whereabouts her friends kept close about it"