as a noun, 'blur' refers to a thing that cannot be seen, heard, or recalled clearly. It can denote something that is out of focus or not distinct.
'blur' as a noun can refer to an unclear or indistinct image, sound, or memory.
The car sped past in a blur.
The evening was a blur of laughter and dancing.
From a distance, the text was just a blur on the page.
as a verb, 'blur' means to make or become unclear or less distinct, either in terms of visual clarity or in terms of distinction between concepts or feelings.
'blur' as a verb can refer to the act of making something less clear or distinct, or the process of something becoming less clear or distinct.
Tears began to blur her vision.
Over time, the memories started to blur and merge together.
Don't blur the lines between right and wrong.
the term 'blur the lines' is an idiomatic expression meaning to make the distinctions between two concepts or categories less clear. 'Blur' can be used in various contexts, from photography (where something out of focus becomes a blur) to emotions or memories (where specifics might become less distinct over time).