Chihuahua's typically weigh less than 10 lbs. Have you ever see one in a lady's purse? I have.
Like many other small dogs, the Chihuahua can display above-average aggression toward people and other dogs. The American Kennel Club does not recommend it for families with young children. However, they tend to be mildly good with other dogs!
I think of a Chihuahua as fiesty with a large personality - offsetting the size of the dog itself.