Noun, Noun which may take the genitive case particle 'no'
bittersweet; having mingled feelings of joy and sorrow; joy and sorrow alternating in one's heart
Yojijukugo (four character compound)
私の胸中は悲喜こもごもだ。Joy and grief alternate in my breast.
Also written 悲喜交交【ひきこもごも】、悲喜交々【ひきこもごも】