Inseparable verbs are also compound words. They consist of a prefix and a stem. Some examples:

be.suchen: Ich besuche meine Eltern. I visit my parents.
ent.stehen: Hier entsteht ein neues Einkaufszentrum. Here a new shopping mall is being built.
er.zählen: Ich erzähle dir (mal) was. I will tell you something.

As you can see, the prefixes be-, ent-, er- do not separate from their stems, ever! But as before with the separable verbs, they often change the meaning of the stem verb significantly:

suchen > to search vs besuchen > to visit
stehen > to stand vs entstehen > to emerge
zählen > to count vs erzählen > to tell

Which verbs are inseparable?

Some of the more important inseparable prefixes are:

be-ent-er-ver-zer-ge- and miss-

and I have written them down in this particular order for a reason:

If you learn these prefixes as one new „magic“ word like you have hopefully done with the article signals, you will be able to remember the inseparable prefixes quickly, without having to think at all. So, imagine Hermann Potter, wizard apprentice, trying to fix our problem of prefixes separating from their stems. He creates a new spell especially for this purpose, but, as he‘s only an apprentice, he is not as powerful as he would have liked. So he manages to fix only a few prefixes for us. The ones mentioned above. If you remember his spell, you remember the most important inseparable prefixes. Here it is:

BE - ENT - ER - VER - ZER - GE - MISS

Say this spell out loud several times until you can recite it flawlessly. Be precise because as with every magic spell, a mistake can be fatal (for your correctness).