Nope.
A blazer is an "odd" jacket, i.e. not part of a suit, but it is (should be) styled differently from a sports or casual jacket. Though modern usage blurs the distinction.
Properly has patch pockets without flaps, and has a history evolving from naval to yachting to boating to smart sports.
Due to its history it is often navy blue and may have brass buttons. May have a regimental or club badge on the breast pocket
Club blazers may be in garish colours or patterns
For men, is considered one step down in formality from a lounge suit, but can be rendered more casual by choice of trousers and shirt.