It looks like a Geranium of some variety (assuming its not producing tall flowering stems, when it might be Delphinium); these are hardy herbaceous perennials, and not to be confused with Pelargonium, which has the common name of geranium. All varieties spread to differing extents, and some seed themselves readily; most tolerate shade, but prefer partial shade. There are hundreds of varieties, not sure which one this is, seeing open flowers would be helpful, as well as knowing the height. This link https://www.gardenia.net/guide/Long-Blooming-Hardy-Geraniums-for-your-Garden lists some varieties of Geranium, though judging by the foliage, I don't think yours is one of them. If its got too big, you can dig it up, split it in half and replant one of the halves... but that's best done in early spring or mid to late autumn, so if you do it now, keep the replanted section well watered.