It's not compost, it's anaerobic liquid sludge, likely with a very high excess nitrogen content which is presenting itself as a horrible ammonia smell. You've got two choices - you can either add lots of 'brown' materials and mix it all up, preferably wearing a mask, or tip it out and spread it somewhere it won't cause harm to plants till it dries out and the smell has dissipated, then use it or mix it back in the compost bin with other materials.
Compost that's ready for use should not smell nasty, and looks like dark soil with a crumbly texture. Compost heaps or bins need to be built in a certain ratio of brown to green material known as the CN ratio - around 25 to 30 parts brown (carbon) to 1 part green (nitrogen). If all that went in the compost bin was grass cuttings, that's high nitrogen material, all green in other words, and this noxious sludge is the result. This link https://www.planetnatural.com/composting-101/making/c-n-ratio/ should be helpful in describing green and brown materials and their CN values, and has a link to general information on composting.