Gemini's are excellent communicators, known for their fast, clever and curious minds, thirst for knowledge and desire to share it with others. They tend to be highly enthusiastic, impulsive and objective. On the negative side they tend to be criticized for being unemotional, superficial and indecisive.
Intelligent
Generous
Friendly / sociable
Outgoing
Easy going
Quick witted / clever
Interesting
Exciting
Charismatic
Persuasive
Sociable
Independent
Flexible
Adaptable
Balanced
Curious (bad side = nosy!)
Rarely possessive or jealous
Extrovert
Self confident
Optimistic
Objective
Impulsive
It's worth noting that most good Gemini traits and characteristics have an equal and opposite bad trait or characteristic. For example, someone who is highly analytical could be described as either intelligent (good) or unemotional (bad). Someone who is spontaneous (good) is also impulsive (bad).
Flirtatious
Unemotional
Superficial
Unreliable
Indecisive
Sarcastic
Devious
Flighty
Restless
Moody (rare for an unemotional sign)
Impulsive
Lack perseverance
Talking
Partying
Dreaming
Meeting new people
Trying new things
Change, variety
Boredom
Routines
Feeling restricted
Rules
One of the fascinating things about astrology is the patterns which exist. Gemini personality traits certainly aren't random. They come from a combination of the signs ruling planet, element, polarity, house and quality. All of these are also used (consistently) elsewhere within astrology and come together to form the unique package which is the Gemini personality.
No. The above traits exist if someone has a Gemini sun sign. However every individual also has other planet placements (Moon, Mars, Venus etc) which modify this behavior. In some cases one or more of the basic personality traits listed above will be modified or even replaced. Only by examining all the planet placements for an individual can we get a complete picture of their unique personality. A skilled astrologer can often calculate these backwards from the ways that the basic sun sign behavior is being modified.
As children we are subjected to many experiences and influences. These can lead to a determined effort to modify our personality and behavior. The traits still exist, but they can be over ridden by free thought. It's fairly common for negative traits to gradually diminish as a person gets older, wiser and more socially adept.