Sihdir is a turkish phrase for saying go away or fuck off or piss off.when some one says something stupid or unbelieveable,saying sihdir can show your srpurize.this phrase is very informal and offensive.
A: galiz bu geja gedax kharida.
B: sihdir.sabah imtahanim var
A: let's go shopping tonight.
B: sihdir.i have exam tomorrow.