-siktir is a verbal cursing,the best translation would be "gtfo" get the fuck off. its more like denieing someones action than just saying gtfo like "fuck that "
rick : you can trust me your lil secrete u know we ´re best buddys
bob : hasiktir
rick : i´ve met jessica alba last night in the v.i.p. section of the club
bob : siktir .. your momma told me u were sleeping