Hello Gaurav,
I am agree with the explanation given by ravil and want to add that equaulizer performs modest cuts or amplify the amplitude of signal across the range of frequencies to improve the response.Equalizer consist of filter stages. Simple EQ is provided with just a cut/boost control for each frequency band. More complex designs go on to offer adjustable turnover frequencies and possibly some adjustment of Q or bandwidth as well. The most flexible form of EQ is parametric EQ, which provides frequency, bandwidth and cut/boost controls.
Filters are generally described as cut-only devices that are intended to remove some portion of the frequency spectrum.
Regards