There is no real answer because some word - like seniority - do not have antonyms or synonyms. You could say that it is "short living." That would be an accurate antonym. So yeah. Hope I could help.
Seniority is the length of time a person has worked for an employer. IE: the person with the most seniority has worked there longer.
Seniority overlooks ability.
SENIORITY - the state of being elder (senior) in age or experience Example : "Congressional assignments are based on seniority." Example : "The employees were paid bonuses based on their seniority in the firm."
seniority list according to the employment registration
Seniority means age - the older a horse the more senior they are.
Seniority is no longer absolute in selection of committee chairs, but it is usually followed
seniority
Seniority is gained by logging in to the game on separate days. To reach a seniority of 30 you must log in on 30 different days.
Spanish people use the word seniority instead of saying women or girl.
Sewing, Dharmapuri District Seniority list
New ideas are discouraged from the seniority rule