謹啓[kinkei] Dear Sir or Madam
啓く[hiraku] to enlighten
啓示[keiji] revelation (i.e. divine revelation)
啓発[keihatsu] enlightenment
啓蒙[keimou] enlightenment

啓蟄[keichitsu] "awakening of insects" solar term (approx. Mar. 6, the day on which hibernating insects are said to come out of the ground)
天啓[tenkei] (divine) revelation
拝啓[haikei] Dear (so and so)
啓上[keijou] speaking respectfully
啓迪[keiteki] edification

愛敬[aikyou] charm
愛敬のある[aikyounoaru] charming
畏敬[ikei] reverence
恭敬[kyoukei] respect
敬う[uyamau] to show respect

敬愛[keiai] respect and affection
敬意[keii] respect
敬遠[keien] pretending to respect someone while in fact staying distant from him
敬具[keigu] Yours sincerely
敬語[keigo] honorific