Vairagyam Gneyamapritiha Shreekrushnetaravastushu - Vairagya is explained in the first half of this Shloka. Vairagya is non-attachment or displeasure in things other than Lord Shree Krishna. Vairagya is renouncing all material things that give pleasure and finding pleasure in devotion to God.
Gnaanam Cha Jivamayesharupanaam Sushtu Vedanan - The second half of the Shloka discusses the nature of Gnaan - supreme knowledge. Such Gnaan is the understanding of the entities Jiva, Ishwar and Maya.
Jiva is the in-dweller of the body. It is the life force of the body which makes it active - able to walk etc. He is the owner of the body (thus the soul is separate from the body.)
Maya is Prakriti or nature and Ishwar is Paramatma or God Supreme. Knowledge of these is Gnaan. The Gita explains ‘Knowledge of Kshetra (body) and Kshetrajna (soul) is Gnaan.’ Jiva, Maya and Ishwara are briefly explained over the next three Shlokas.