na-adjective, noun
profound; deep; full of meaning
Almost exclusively used in the compound 意味深長 (いみしんちょう), meaning 'pregnant with meaning' or 'suggestive'. Rarely used independently.
彼の言葉は意味深長だった。
His words were full of deep meaning.
その映画のラストシーンは意味深長で、観客に強い印象を残した。
The final scene of the movie was profound and left a strong impression on the audience.