an amateur who engages in an activity without serious intentions and who pretends to have knowledge
An amateur, someone who dabbles in a field out of casual interest rather than as a profession or serious interest.
showing frivolous or superficial interest; amateurish
"his dilettantish efforts at painting"
Pertaining to or like a dilettante.
The word comes from the Italian dilettante, which is the present participle of dilettare. It originally meant "to delight" and traces back to the Latin verb dēlectāre.