ancestor, antecedent, ascendant, ascendent, root - someone from whom you are descended (but usually more remote than a grandparent)

grandparent - a parent of your father or mother

great grandparent - a parent of your grandparent

leave alone, leave behind, leave - leave unchanged or undisturbed or refrain from taking; "leave it as is"; "leave the young fawn alone"; "leave the flowers that you see in the park behind"

let it go - not act; "He thought of a reply but let it go"

abstain - refrain from voting

spare, save - refrain from harming

help oneself, help - abstain from doing; always used with a negative; "I can't help myself--I have to smoke"; "She could not help watching the sad spectacle"

stand by - not act or do anything; "He just stood by when the police beat up the demonstrators"

sit out - not participate in (an activity, such as a dance or a sports event); "He sat out the game"