Excessive means far more than there should be. Excessive noise from the flat upstairs, excessive salt in the soup, an excessive charge at the bottom of the bill.
It is a judgement, not a measurement: excessive never says how much, it says too much, and it always disapproves. It goes with the nouns people complain about — excessive force, excessive drinking, excessive delay, excessive heat, excessive packaging. The adverb behaves the same way, as in excessively long meetings, and the noun is excess: in excess of, drink to excess, excess baggage. With people it prefers the behaviour to the person, so you would call someone's demands excessive rather than the person. Do not reach for it when you only mean very big — an excessive crowd sounds like a complaint about the number of people, because it is one.
Excessive arrived through Old French excessif and Middle English excessif, from Medieval Latin excessivus. Take it apart in modern English and it is exactly what it looks like: excess plus -ive, the ending that turns a thing into the quality of having it.
Medieval Latin
excessivus
Old French
excessif
Middle English
excessive
English, today
excessive
From Middle English excessive, excessif, from Old French excessif, from Medieval Latin excessivus, equivalent to excess + -ive.
Etymology from Wiktionary, CC BY-SA