1. vague
2. unclear, dark
3. incomprehensible, uncomprehensible, hidden
4. concealed, unknown
5. unsung, inglorious, dishonorable, unnoticeable
6. inconspicuous, invisible, apart

1. isolated, unconnected, befog
2. becloud, obnubilate, haze over, fog, cloud, mist, hide, conceal, confuse
3. blur, obnubilate, change, alter, modify, bedim
4. overcloud, change, alter, modify, blot out
5. obliterate, veil, hide, change, alter, modify, benight
5. bedim, darken