Question

let off steam "means​

Answer 1

$\huge\mathfrak\red{Answer :) }$Lit. [for something] to release steam. The locomotive let off some steam after it came to a halt. With a great hiss, it let off steam and frightened the children. 2. Fig. to work or play off excess energy. Those boys need to get out and let off some steam. Go out and let off steam! 3.

Answer 2

Explanation:

To get rid of energy or express strong feeling by behaving in a noisy or wild way...