incredible UK /ɪŋˈkɹɛdɪbəl/US /ɪŋˈkɹɛdəbəl/ adjective3 •Too implausible to be credible; beyond belief.The extinction of a species once so numerous seemed incredible. — 1955 •so great or surprising that it fills people with wonderHe was so wrapped up in watching the incredible special effects that he couldn't keep track of the story. •Marvellous; profoundly affecting; wonderful; excellent.I had such an incredible slice of pizza last night that I simply can't think about anything else. formsmore incredible · most incredible