The usual term is defocused or out of focus. “Bokeh” is not the right search term here: bokeh refers to the quality of the out-of-focus areas, often with a subject still sharp and sometimes visible blurred highlights.

For your use case, try searches such as:

• defocused photo
• out of focus image
• fully out of focus
• blurred due to focus

If you’re building a blur detector, note that these are specifically defocus blur images, not just any blurred image. Also, one answer pointed out that for simple blur detection, a neural network may be unnecessary: checking for weak or absent strong edges across the frame can often identify heavily blurred images.