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

杜父魚[tofugyo] sculpin (any fish of family Cottidae, inc. the bullheads and the miller's-thumb)
杜撰[zusan] careless
杜漏[zurou] careless
杜宇[hototogisu] lesser cuckoo (Cuculus poliocephalus)
杜夫魚[kakubutsu] fourspine sculpin (species of fish, Cottus kazika)

杜絶[tozetsu] stoppage
鎮守の杜[chinjunomori] grove of the village shrine
杜氏[touji] chief brewer at a sake brewery (after name of sake's alleged inventor)
杜若[kakitsubata] rabbitear iris (Iris laevigata)