愛妾[aishou] beloved concubine
妾腹[shoufuku] illegitimate (e.g. born to a mistress)
妻妾[saishou] one's wife and mistress(es)
男妾[danshou] male paramour
妾出[shoushutsu] illegitimate (e.g. born to a mistress)

妾宅[shoutaku] house in which a mistress is kept
蓄妾[chikushou] keeping a mistress (concubine)
外妾[gaishou] foreigner's mistress
洋妾[youshou] Westerner's mistress

公私[koushi] public and private
公平無私[kouheimushi] impartiality
私の場合[watakushinobaai] in my case
私宛[watashiate] my address

私儀[watakushigi] as for me
私刑[shikei] lynching
私見[shiken] personal opinion
私財[shizai] private funds