弱化 is read as じゃっか (jakka) and means weakening.
じゃっか
jakka
じゃくたいか
weakening
じゃくどくか
attenuation
じゃくへんかどうし
weak verb
じゃくてん
weak point
よわき
bearish
よわみ
(a) weakness
よわい
weak
よわね
feeble complaint
よわまる
to abate
よわめる
to weaken
よわる
to be downcast
よわむし
coward