whim 
/ˈwɪm/ noun
plural whims /ˈwɪm/ noun [count] : a sudden wish, desire, decision, etc.
▪ the whims of fashion ▪ It's hard to predict voters' whims. ▪ Her husband tries to satisfy her every whim. [=make her happy by doing everything that she wants] ▪ He quit his job on a whim. [=because of a sudden decision] ▪ The shop is only open at the whim of the owner. [=the shop is only open when the owner wants it to be open]
▪ the whims of fashion ▪ It's hard to predict voters' whims. ▪ Her husband tries to satisfy her every whim. [=make her happy by doing everything that she wants] ▪ He quit his job on a whim. [=because of a sudden decision] ▪ The shop is only open at the whim of the owner. [=the shop is only open when the owner wants it to be open]
