"Laggy" means something is slow or delayed, often referring to technology or internet connection that takes longer to respond or load than expected. Full definition
The low light performance of the V30 + is pretty average as result often turn out to be a little grainy and the camera app is also little laggy in low light environments — the large aperture does pull in more light and makes even objects in dark areas visible, but this benefit is offset by the amount of noise that creeps into the images. (techpp.com)
It can be a bit laggy at times but other than that it is pleasantly fun. (jgghgames.com)
Some Google Nexus 6P users experiencing laggy performance and app crashes after November security patch (nashvillechatterclass.com)