The term 'adder relative' refers to a group of snakes that are related to the adder, which is a venomous SNAKE found in Europe and North America. The crossword solutions for this term include ASP (3 letters), SNAKY (5 letters), VIPER (5 letters), SNAKE (5 letters), and VENOM (5 letters). An ASP is a type of venomous SNAKE found in Africa and Asia, while a VIPER is a venomous SNAKE found in Europe, Africa, and Asia. SNAKY and SNAKE are both terms used to refer to any type of SNAKE, and VENOM is the toxic substance produced by snakes. All of these terms are related to the adder, which is a venomous SNAKE found in Europe and North America.