Presumptuous means taking a liberty you have no right to take. A presumptuous question, forgive me if this is presumptuous, presumptuous of him.
It is what people say before doing exactly the thing — it may be presumptuous of me, but — and the apology is part of the manoeuvre. Note the spelling: two u's, and it is not presumptious, however often that is written.
1adjectivepresumptuousTaking a liberty you have no right to take.
“It was presumptuous of him to book the holiday before asking whether I could go.”
presumptuous is a quality.
Latin praesumptuosus comes from praesumere, to take beforehand — prae, before, plus sumere, to take.
Old French
presumptieus
Middle English
presumptuous
Latin
sūmptus
English, today
presumptuous
From pre- Latin sūmptus -uous, from Middle English presumptuous, borrowed from Old French presumptieus, presumpcieus, presumptuos, from Latin praesumptuosus.
Etymology from Wiktionary, CC BY-SA