deffo /ˈdɛfəʊ/adjective 1adverb 1forms 2 adjective1 •(UK, informal) Definite.I know for certain they′re not speaking to each other, that′s for deffo, not that I′ve even seen them in the same room over the last week to confirm their silence. — 2003 adverb1 •(UK, informal) Definitely.He told me that he's deffo going to be there tonight. formsmore deffo · most deffo
