arm
A shot in the arm.
in
This idiom or expression means:
A booster.
A helpful deed.
A. Did you get a year end bonus?
B. Yes, and what a shot in the arm it was just when I really needed one!!
At arm's length.
This idiom or expression means:
At a distance.
When someone says “He’s been allowed to manage the project at arm’s length,” they mean “He’s not allowed to have full control of the project.”
Also, in law or real estate:
“At arm’s length” refers to a transaction between parties who are not related to each other.
They came back, arms longer than legs.
They came back without any success.
