Of or relating to a fan, but especially to fandom(adjective)
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Use "fannish" in a sentence
"For the record, I do not support the "outing" of people who participate in fannish or other online activities under a pseudonym."
"In summary, Terror Firma is probably the best of these in fannish terms, Thicker Than Water probably the most approachable for the non-fan."
"We've attended over 200 of them, including some that have gone down in fannish history for their ineptitude, such as the 1968 Baycon, the 1988 Nolacon II, and the 1993 ConFrancisco (forever known as ConFiasco)."