There is no difference between the meaning of Fardh and Wajib according to majority of Sunni scholars ( Shafi'ee, Maliki, and Hanbali sects) except Abu Haneefa sect who say that Fardh is what has come as an obligatory in Quran, while Wajib is according Hanafi sect is the obligatory which came in Sunnah.
Shia Ulama have no difference in the meaning of Fardh and Wajib as both mean obligatory.
'Wassalam.