mutability in life or nature (especially successive alternation from one condition to another)
a variation in circumstances or fortune at different times in your life or in the development of something; "the project was subject to the usual vicissitudes of exploratory research"
not capable of being precisely or readily described; not easily put into words; "an indefinable feeling of terror"; "an abstract concept that seems indefinable"
defying expression or description; "indefinable yearnings"; "indescribable beauty"; "ineffable ecstasy"; "inexpressible anguish"; "unspeakable happiness"; "unutterable contempt"; "a thing of untellable splendor"
substitute a person or thing for (another that is broken or inefficient or lost or no longer working or yielding what is expected); "He replaced the old razor blade"; "We need to replace the secretary that left a month ago"; "the insurance will replace the lost income"; "This antique vase can never be replaced"
put something back where it belongs; "replace the book on the shelf after you have finished reading it"; "please put the clean dishes back in the cabinet when you have washed them"