- 秘密【ひみつ】 - secret, secrecy, confidentiality, privacy, mystery, secret (e.g. to success), esoteric teachings 
- 秘書【ひしょ】 - (private) secretary, treasured book, secret book 
- 秘める【ひめる】 - to hide, to keep to oneself 
- 秘訣【ひけつ】 - secret (method, trick, etc.), key (e.g. to success), mysteries (of an art, trade, etc.), recipe, trick 
- 神秘【しんぴ】 - mystery, mysteriousness, secret 
- 神秘的【しんぴてき】 - mysterious, mystical 
- 便秘【べんぴ】 - constipation 
- 黙秘権【もくひけん】 - right to keep silent, right to silence, right to remain silent 
- 秘話【ひわ】 - secret story, unknown episode 
- 黙秘【もくひ】 - remaining silent, keeping secret 
- 秘境【ひきょう】 - unexplored region, secluded region, place off the beaten track 
- 秘策【ひさく】 - secret plan, secret scheme, secret stratagem, secret method 
- 秘蔵【ひぞう】 - treasuring, cherishing, prizing, holding dear 
- 秘伝【ひでん】 - secret (recipe, medicine, etc.), mysteries (e.g. of an art) 
- 秘匿【ひとく】 - hiding, concealment