IPA: //ʌnˈsɪmətrɪkəl//
KK: /ʌnˈsɪmɪtrɪkəl/
Not having a balanced or equal shape on both sides; lacking symmetry.
The design of the building is unsymmetrical, with one side much larger than the other.
Unsymmetrical → It is formed from "un-" (meaning not) and "symmetrical" (from Greek "symmetria", meaning proportion or measure together). The word "unsymmetrical" means not having proportion or balance in shape or arrangement.
Think of 'not' ('un-') having 'balance' or 'proportion' ('symmetrical') — that's why unsymmetrical means lacking symmetry.