(Bear in mind that my answer is based partially on theory and partially on experience so it may not look 100% like other answers as it also includes my personal experiences.)
INFJs are people-oriented. Yes, they are introverts and yes, many of them are extremely shy, but one thing that sets INFJs apart from INTJs is their need for social harmony. This comes from their auxiliary function, Fe (extroverted feeling), meaning that they tend to value the feelings of others and are often very socially astute. They know what is acceptable in a social situation without needing to think about it and naturally prioritise the needs of the group as a whole.
In contrast, INTJs’ auxiliary function is Te (extroverted thinking). This means that they judge how to respond to a situation via logical deduction. INTJs value efficiency and often get the reputation of being ‘cold’ as they do not mind sacrificing someone’s feelings to get the job done, and done well. One misconception is that INTJs are inapt when it comes to socialising. For me, I am highly introverted and need time completely alone without strong external distractions to re-charge. However, I can be pleasant and indeed talkative among others. The only issues for me are that I quickly drain energy whilst socialising and end up feeling unhappy, and that I have to consciously think about what I am saying and how it could affect the others in the group- this ability just doesn’t come naturally to me.
INFJs tend to idealise. They want to see people as good, however this can lead to disappointment or sadness when they start to see the numerous negative qualities of their fellows.
On the other hand, INTJs tend to be cynics. They see people in a much harsher light and are more ready to believe in their flaws than their INFJ counterparts.
Finally, INFJs are usually more open than INTJs. They do not mind talking about their feelings and seek to appease those around them. They can even feel guilt for focussing on their own emotions if they are around people who suppress theirs, and feel a need to reach out to these people and talk to them (whether that need is acted on or, more likely, not).
INTJs are masters at bottling up their emotions. They don’t want to talk about them and don’t want to think about them. If an INTJ is going through a hard time, they will likely keep this information to themselves. (INFJs tend to do this also, but more for the fact that they do not want to burden others with their problems, rather than they feel inable to do so.) This can lead to those close to the INTJ being worried about their increasing quietness, or alternatively their loud outbursts, whilst feeling helpless to do anything about it.
Please note that I have only talked about the more observable, ‘concrete’ differences between INFJs and INTJs to answer the question more appropriately and to avoid confusion. There are also many other differences between the two types, but I didn’t want my answer to go on any longer than it already is haha.
Thanks for taking the time to read this all, if you got this far, and I hope this helped!
1.2K viewsView 51 upvotesView shares