気密 is read as きみつ (kimitsu) and means airtight.
きみつ
kimitsu
きみつせい
airtightness
きみつしつ
airtight chamber
こうきみつ
good airtightness
きざ
affected
きがね
constraint
きじょう
stout-hearted
きほう
(air) bubble (esp. in a liquid)
きはく
spirit
きづかい
consideration
きがい
strong spirit
きかんしえん
bronchitis
きづかう
to worry about (someone's welfare or comfort)