What do all of these letters mean?
They are from the Myers-Briggs type indicator; which is a questionnaire that leads to a four letter type. You can use this as a lens with which to analyze yourself and others. The letters with shallow explanation:
E vs I - Extravert vs Introvert. Where at your first do you get energy? Are people energizing? Are they draining? Do you like large groups? Small groups?
S vs N - Sensor vs Intuitive. Are you present in the now and information from your surroundings? Do you take cognitive leaps and build patterns easily?
T vs F - Thinker vs Feeler. Are you objective or subjective? Do you logic first or emotion first?
J vs P - Judger vs Perceiver. Do you want a decision made now? Do you want to explore options and leave things open?
These four letters actually stand for eight letters, or four cognitive functions. I’m an INFJ, my set is: Introverted Intuition, Extraverted Feeling, Introverted Thinking, Extraverted Sensing. Introverts can extravert. Thinkers feel, feelers think. The N & S are information based, how we take in data. The F & T are judgment based, what we do with our information.
(take it at a couple places to make sure you’re consistent. You should never get an X, except maybe on the I vs E because they connect to cognitive functions.)
Cognitive functions: Fence-Building from - http://www.famoustype.com/functions.htm
The Eight Functions and Fence-Building
Ne - I want to design the fence.
Ni - Why do they want to do this and what is the deal with fences anyway? Is this necessary?
Se - I want to decorate the fence and make sure that it looks stylish and appealing
Si - I’ll take care of looking at the instructions and making sure that we follow the established guidelines.
Te - Is doing this cost effective? Will it be useful?
Ti - I want to analyze the structure and placement of the fence.
Fe - How will it affect the neighborhood, and what will the neighbors think?
Fi - I want it to be my own special fence that I can share with others over time
ENFP - Ne / Fi / Te / Si
ENTP - Ne / Ti / Fe / Si
ESFP - Se / Fi / Te / Ni
ESTP - Se / Ti / Fe / Ni
ENFJ - Fe / Ni / Se / Ti
ENTJ - Te / Ni / Se / Fi
ESFJ - Fe / Si / Ne / Ti
ESTJ - Te / Si / Ne / Fi
INFP - Fi / Ne / Si / Te
INTP - Ti / Ne / Si / Fe
ISFP - Fi / Se / Ni / Te
ISTP - Ti / Se / Ni / Fe
INFJ - Ni / Fe / Ti / Se
INTJ - Ni / Te / Fi / Se
ISFJ - Si / Fe / Ti / Ne
ISTJ - Si / Te / Fi / Ne