Imagine you're playing with your friends and you decide you want to build a big sandcastle. You grab your toy bucket and shovel and start piling up the sand. But you haven't actually finished building the castle yet, because you haven't added any towers or decorations.
An inchoate offence is kind of like that unfinished sandcastle. It's a crime that you haven't quite finished committing yet. Maybe you've taken some steps towards committing the crime, but you haven't actually carried it out yet.
For example, let's say you want to rob a bank. You might start by researching the bank's security systems and figuring out the best way to get in. Or maybe you'll buy a mask and a gun. These things are all part of planning for the crime, but you haven't actually robbed the bank yet.
Inchoate offences are still considered crimes because they show that you had the intention to commit the crime. Even if you never actually follow through, the fact that you made plans or took steps towards the crime is still seen as a serious issue.
So basically, an inchoate offence is like an unfinished crime. It's still a problem because it shows that you wanted to do something illegal, even if you never actually went through with it.