what does this mean when it's in a job description? iv googled it and still can't find anything :-/
they are loaded with prejudices, not based upon anything in reality,but based on... if something is new, they reject it immediately because itís frightening to them. what they do instead is just stay with the familiar.
Substantive post/position generally means that it's your main role.
For example, if you go on secondment (you do another job for a fixed amount of time), you could refer to the job you usually do as your substantive position. Or, it could be used referring to someone on maternity leave who comes back to take up their substantive post (eg the job they had before they went on maternity leave).
It's difficult to know what it means in a job description without knowing the context, but if it's unclear why not contact the employer and asking them to explain what this means in terms of the role.
"You can not become if you only said what you would have done." So Do-it.