secret ballot

词形变化：

副词: secretly |

同义词：

private | covert | confidential | mystery | underground | clandestine | hidden | secluded | mysterious | furtive | underhanded | enigma | top-secret | surprise | classified | concealed | confidence | skeleton in the cupboard | riddle | inner | in | dark | unknown | stealthy | inmost | significant | closet | enigmatic | anonymous | invisible | inward | surreptitious | intimate | inwards | privy | unavowed | hush-hush | undercover | hole-and-corner | arcanum | mystical | mystic | cloak-and-dagger | closed book | occult | hugger-mugger |

反义词：

open |