In the video "ugly defense", GM Grigoyan called the move Knight g3-h1 an "ugly move", though objectively speaking, Nh1 may be the best move for white in this position.
[fen "r1b2rk1/b1p4p/p1pp1qp1/P7/4P1n1/3N2N1/1PP2PPP/R1BQ1RK1 w - - 1 1"]
May I know if there is a definition of an "ugly move"? In my humble opinion, if a move is objectively the best in a particular position, it should be called a "good move", or sometimes a "brilliant move", or sometimes a "forced move", or sometimes a "book move". In this position, I would call Nh1 a "forced move".