動詞 crumble:

1. fall apart
   同義詞：crumple, tumble, break down, collapse
2. break or fall apart into fragments
   同義詞：fall apart
3. fall into decay or ruin
   同義詞：decay, delapidate

1. The earthquake made the wall sink and start to crumble.
   這次地震把這堵墻震得下陷并開始崩塌。
2. He crumbled the bread in his fingers.
   他用手指把面包捏碎了。
3. Most of the paint had crumbled off.
   油漆大都剝落。

crum.ble

v.（動詞）
crum.bled,crum.bling,crum.bles
v.tr.（及物動詞）
To break into small fragments or particles.
弄碎：把…弄碎成小塊或小粒
v.intr.（不及物動詞）
To fall into small fragments or particles; disintegrate.See Synonyms at decay
碎裂，破碎：碎裂成小塊或小粒；破碎參見 decay
To give way; collapse:
失敗；崩潰：
例句：
an ego that crumbles under pressure.
一個在重壓下衰敗的時代

來源：
Alteration influenced by crumb
受 crumb的影響
of Middle English cremelen
中古英語 cremelen的變化
from Old English *crymelen [frequentative of] gecrymmian [to break into crumbs]
源自 古英語 *crymelen [] gecrymmian的重復動詞 [碎裂成碎屑]
from cruma [crumb]
源自 cruma [碎屑]