1
general::
Sit down, relax, as in I wish you'd take some time and take the load off. A shortening of take the load off one's feet, this colloquial phrase dates from about 1940. It is sometimes put as take a load off. take the plunge Venture something, commit oneself, as in You've been living together for a year, so when are you going to take the plunge and get married? It is Also put as make the plunge, plunge alluding to diving in a body of water. [Mid-1800s]
American Heritage Idioms