a walking (something)
The living embodiment of something; a person who has or displays the characteristics of something. First, I lock myself out of the house, then my grocery bag breaks in the parking lot, and now I stepped on my glasses—I'm just a walking disaster today! If you've ever had to spend a lot of time with kids, you know they're basically just walking petri dishes of germs and bacteria.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
If you describe someone as a walking something, you mean that they are an example of that thing or have the characteristics of that thing. She was seen by both lay people and clerics as a walking miracle. Wayne is a walking disaster.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012
a walking —someone who notably embodies the characteristics of something. informal
1989 Charles Shaar Murray Crosstown Traffic He is…a dubious political philosopher and a walking disaster area as a businessman.
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