Influential means able to shape what others think or do. An influential figure, hugely influential, an influential paper.
It is about effect rather than fame — an influential paper may be unread outside its field. It says nothing about whether the influence was good, which is why it can be used of people nobody admires without contradiction.
1adjectiveinfluentialAble to shape what others think or do.
“Her book was so influential that it changed how doctors treat back pain.”
influential is a quality.
Medieval Latin influentialis comes from influentia, a flowing in, from influere — in plus fluere, to flow.
Medieval Latin
īnfluentiālis
English, today
influential
From Medieval Latin īnfluentiālis, from īnfluentia + -ālis. by surface analysis, influence + -ial.
Etymology from Wiktionary, CC BY-SA