Swarming (with) is a term used to describe a large group of people or animals that are gathered together in a dense mass. The crossword solutions for this term are TEEMING (7 letters) and RIFE (4 letters). TEEMING is an adjective that means filled with a great number of people or things, while RIFE is an adjective that means abundant or existing in large numbers. Together, these two words accurately describe the concept of swarming (with).