tight–lipped

tight–lipped /ˈtaɪtˈlɪpt/ adjective
tight–lipped
/ˈtaɪtˈlɪpt/
adjective
Britannica Dictionary definition of TIGHT–LIPPED
[more tight–lipped; most tight–lipped]
1 
: not willing to speak about something
2 
: having your lips pressed tightly together because you are thinking hard, angry, etc.