assumption

labor under (something)

To live, function, or operate while believing something or holding an assumption of some kind, especially something that is not or may not be true. We all labored under the assumption that we would be getting paid overtime, so we all nearly quit when we realized that wasn't the case These politicians want us all to labor under the notion that they're our friends, looking out for our interests first and foremost.

See also: labor

labor under an assumption

Fig. to function or operate believing something; to go about living while assuming something [that may not be so]. I was laboring under the idea that we were going to share the profits equally. Are you laboring under the notion that you are going to be promoted?

See also: assumption, labor