Fetching details from the dictionary...
substance; essence
substantive; substantial; essential; real (e.g. interest rate)
in essence; in effect; essentially; effectively; practically
parenchyma
彼が実質的なリーダーです。
He is the actual leader.
実質的な変化はありませんでした。
There was no substantial change.
この会議は実質的に決まっています。
This meeting has been essentially decided.