Definition of funtastic in US English:

funtastic

adjective

informal
  • Extremely enjoyable or entertaining.

    ‘she had herself a pretty funtastic weekend’

Origin

Late 19th century (in Fun-tastic fictions, the title of a section in the British satrical magazine Fun): blend of fun and fantastic.

Pronunciation

funtastic

/ˌfənˈtæstɪk//ˌfənˈtastik/