1
general::
Lose emotional control, collapse, panic. For example, If she fails the bar exam again, she's sure to go into a tailspin. This expression alludes to the downward movement of an airplane out of control, in which the tail describes a spiral. [Early 1900s]
American Heritage Idioms
2
general::
Phrase(s): go into a tailspin
1. Lit. [for an airplane] to lose control and spin to the earth, nose first. • The plane shook and then suddenly went into a tailspin. • The pilot was not able to bring the plane out of the tailspin, and it crashed into the sea. 2. Fig. [for someone] to become disoriented or panicked; [for someone’s life] to fall apart. • Although John achieved great success, his life went into a tailspin. It took him a year to get straightened out. • After her father died, Mary’s world fell apart, and she went into a tailspin.
McGrawhill's American Idioms And Phrasal Verbs