когда-нибудь означает в английский

one day▼(at unspecified time in the future)
adverb
[UK: wʌn deɪ] [US: wʌn ˈdeɪ]

one of these days▼(one day)
adverb
[UK: wʌn əv ðiːz deɪz] [US: wʌn əv ðiːz ˈdeɪz]

someday▼(sometime; at some time in the future)
adverb
[UK: ˈsʌm.deɪ] [US: ˈsʌm.ˌde]

sometime▼(at an indefinite but stated time in the past or future)
adverb
[UK: ˈsʌm.taɪm] [US: ˈsʌm.ˌtaɪm]

somewhen▼(at some time; indefinitely; some time or other, sometime)
adverb
[UK: sˈʌmwən] [US: sˈʌmwən]