Getting on and Gray-haired

Gray-haired and getting on are semantically related In some cases you can use "Gray-haired" instead an adjective phrase "Getting on".

Gray-haired adjective - Showing characteristics of age, especially having grey or white hair.

Getting on and gray-haired are semantically related in old topic. You can use "Getting on" instead an adjective phrase "Gray-haired", if it concerns topics such as advanced in age.