Well Greek has cases too but I'm going to go with the nominative only
Fem sing = αστεία neut sing = αστείο masc pl = αστείοι fem pl = αστείες neut pl = αστεία
Mind you there are other possible translations too.
"διασκεδαστικός, διασκεδαστική, διασκεδαστικό /διασκεδαστικοί, διασκεδαστικÎÏ‚, διασκεδαστικα" is another good translation
NOTE: Both of the above have the meaning of "amusing" not "strange"
Funny (strange) would be πεÏίεÏγος πεÏιÎÏγη πεÏίεÏγο πεÏίεÏγοι πεÏίεÏγες πεÏίεÏγα