Adverb (fukushi), Adverb taking the 'to' particle
deeply; keenly; severely; completely; utterly
Usually written using kana aloneOnomatopoeic or mimetic word
彼は、自分の不幸をつくづく考えた。He brooded over his misfortunes. intently; carefully; closely; attentively
Usually written using kana aloneOnomatopoeic or mimetic word
Also written 熟熟【つくづく】、熟々【つくづく】