be/go weak at the knees
go weak at the knees
To become unsteady or flustered due to a strong emotional reaction to someone or something. Hearing the news of my father's sudden death, I went weak at the knees and could barely remain standing. Just thinking about Samantha makes me go weak at the knees.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
be/go ˌweak at the ˈknees(informal) be/become weak because of illness, strong emotion, etc: He felt dizzy and a bit weak at the knees. ♢ Her smile made me go weak at the knees (= with nervousness, love, etc.). ▶ ˌweak-ˈkneed adj. not brave or determined
Farlex Partner Idioms Dictionary © Farlex 2017