Can you post a picture of the entire plant?

If you like the plant, then it is not a weed. If you don't like it, then it's a weed. That's sort of the definition of weeds. When I lived in the Dayton area you could buy Queen Anne's Lace seed and you could buy Queen Anne's Lace herbicide. Some people landscaped with it and some hated it.

What you have pictured is the seed head for what most people would call a weed. It is the shaggy appearance of the area with the seed head spikes sitting up higher than the grass itself that people don't like. Likely this is a grassy weed. There are similar seed heads on crabgrass. I suggest you look at Google Images for crabgrass seeds and see if your grass and seeds match. This time of year crabgrass is seeding heavily.

That's sort of the definition of weeds

Public agencies have other definitions of weeds. Including ones that come with an associated sting that may be imposed when a body is determined to be harboring the most detrimental weeds.

Here is a better pic.

Looks like a lawn that is seeding.

My guess is it's just grass that hasn't been mowed in a while. Neighbors seem to have a lot of it too.

No I mow regularly like once a week. Looks like my grass is tall but it's this long weed that grows in days.

Is it all of what we're looking at in the photo or is it mixed in with turf grass? If it's mixed in, can you show a chunk of just the one in question?

Check out the pictures here for King Ranch Bluestem. I never found a solution for it other than killing all the adjacent grass, too. It is going to take over Texas in the next few years. The state has been planting it in the highway medians for erosion control, but it is the worst invasive species of grass I've seen.