恐らく[osoraku] perhaps
恐れ[osore] fear
恐れ戦く[osoreononoku] to tremble with fear
恐れ入る[osoreiru] to be sorry
恐ろしい[osoroshii] terrible

恐喝[kyoukatsu] blackmail
恐慌[kyoukou] panic
恐妻家[kyousaika] hen-pecked husband
恐妻病[kyousaibyou] wife-phobia
恐縮[kyoushuku] feeling obliged

蒼惶[soukou] hurry
蒼惶として[soukoutoshite] in great haste
恐惶謹言[kyoukoukingen] Very truly yours (a complimentary close used in a letter written in an old epistolary style)

恐惶敬白[kyoukoukeihaku] Very truly yours (a complimentary close used in a letter written in an old epistolary style)
惶遽[koukyo] being afraid and panicked
惶懼[kouku] being struck with awe