哀思 is read as あいし (aishi) and means sad feeling.
あいし
aishi
あはれ
alack
あいしゅう
pathos
あわれむ
to enjoy the beauty of
あいとう
condolence
あいかん
joys and sorrows
あいせつ
pathetic
あいきこつりつ
losing weight and becoming bony because of grief
あいちょう
plaintive strains
あわれげ
sad
あいわ
sad story
あいちょうをおびた
plaintive (melody, tone, etc.)