долговременный означает в английский

long-term [longer-term, longest-term]▼(extending over a relatively long time period)
adjective
[UK: ˈlɒŋ tɜːm] [US: ˈlɔːŋ.ˈtɝːm]

permanent▼(lasting for an indefinitely long time)
adjective
[UK: ˈpɜː.mə.nənt] [US: ˈpɝː.mə.nənt]