mlčenlivý znamená v angličtina

coy [coyer, coyest]▼(reluctant to give details about something sensitive)
adjective
[UK: kɔɪ] [US: ˌkɔɪ]

tacit▼(done or made in silence; implied, but not expressed; silent)
adjective
[UK: ˈtæ.sɪt] [US: ˈtæ.sət]

taciturn▼(untalkative, silent)
adjective
[UK: ˈtæ.sɪ.tɜːn] [US: ˈtæ.sə.ˌtərn]