Could be dill or fennel, definitely not parsley or cilantro.Crushing and smelling the plant should verify which one it is. You could use both in cooking, or keep it as a butterfly host plant.There are other plants with similar foliage so I'm not 100 percent sure,but smelling it is a good start.

It does appear to be Apiaceae but it isn't fennel and I'm dubious about dill. What does it smell like?

Floral,how did you determine it wasn't fennel? Thanks in advance.

Well even without the information about white flowers, fennel has tubular leaflets not flat. This thing is far too flimsy and feathery to be fennel.

Got you.Thanks.

it isn't dill or fennel, both I am very familiar with. Both would have yellow flowers right? This has small white flower and leaves smell faintly like fennel, but somewhat wild and weedy. It has hint of taste like betel leaves, if that helps.

Cyclospermum leptophyllum?

Cyclospermum looks like a good match.Considered a noxious weed in some places.Has a few common names that include the word parsley.So many common names for all these Apiaceae members can make things confusing.

That's more like it. Thank you folks!