隠密[onmitsu] privacy
過密[kamitsu] overcrowding
確率密度関数[kakuritsumitsudokansuu] probability density function
機密[kimitsu] secrecy
機密性[kimitsusei] confidentiality

機密保護[kimitsuhogo] security (e.g. data, password, etc.)
気密[kimitsu] airtight
気密室[kimitsushitsu] airtight chamber
緊密[kinmitsu] rigour
軍事秘密[gunjihimitsu] military secret

ゴミ集積場[gomishuusekijou] village garbage collection point
英字集合[eijishuugou] alphabetic character set
家集[kashuu] poet's poetical works
歌集[kashuu] anthology
画集[gashuu] book of paintings in print

会集[kaishuu] audience
解集合[kaishuugou] set of solutions
寄集め[yoseatsume] mish-mash
寄せ集める[yoseatsumeru] to put together
寄り集まる[yoriatsumaru] to gather together