A: What did she want?
B: 20,000 bucks.
A: 20,000 bucks?
B: 15 years OF BACK alimony. I said, “What alimony? When we split up, I gave you whatever money we had” and you took the car.
Question: I don’t really know the usage or how to use “of back” in English.
Is it okay to just say “15 years alimony”?
Thank you!!!
When a separated or ex-spouse is ordered by a court of law to pay child support or in rarer cases, spousal support (alimony) to the estranged spouse, any amount which has not been paid in the past is colloquially referred to as “back child support” or “back alimony.”
Typically if the enforcement agency has been unsuccessful at collecting monthly support from a former spouse who has not paid court-ordered support over a period of ten years or less, the estranged spouse must go back to court (normally with the help of the enforcement agency) to get a court ordered judgment in the amount of the unpaid support. The unpaid amount is colloquially called “back support” or something similar.
Typically a judgment will expire after 10 years due to the statute of limitations. However, the judgment can in turn be enforced by a WRIT OF EXECUTION, which does two things: orders a sheriff to seize personal property, such as an automobile, and extends the life of the judgment for another 10 years, thus preserving the judgment so that a judge can order a new judgment. A judgment can also be enforced by a SUGGESTION against any bank account the defendant might have or a LIEN against the defendant’s real property, i.e. any house they might own and the property it sits on.
Fifteen years worth of back alimony amounting to $20,000 is equal to approximately $100 per month of unpaid alimony, plus interest.
So in this case, think of BACK as PAST or more correctly PAST DUE. Back alimony is unpaid alimony from the past.
Unpaid alimony over a period of 15 years = Fifteen years worth of past due alimony = Fifteen years of back alimony
from the New Oxford American Dictionary:
back adj. 2 (esp. of wages or something published or released) from or relating to the past: she was owed back pay.
In case Bruce’s comment is too detailed 
Back alimony is like back pay, it’s alimony that has not been paid but is due to be paid. Grammatically, ‘of’ is not tied to ‘back’ in this sentence.
No-one answered your question as to whether you must use back alimony, though you received two excellent answers as to what “back” means.
You asked: Is it okay to just say “15 years alimony”?
Answer: Yes! It would be far less explicit, but it would work too.
A: What did she want?
B: 20,000 bucks.
A: 20,000 bucks?
B: 15 years of back alimony.
I said, “What alimony? When we split up, I gave you whatever money we had” and you took the car.
Clearly tells the listener that it relates to alimony owed from the past
A: What did she want?
B: 20,000 bucks.
A: 20,000 bucks?
B: 15 years of alimony.
I said, “What alimony? When we split up, I gave you whatever money we had” and you took the car.
In this context, it is equally clear without the use of “back” that it relates to alimony owed from the past.
If someone said: “We divorced this time last year and I want my alimony”, it would be equally understood to mean back alimony.
You don’t always need to use “back” alimony, it adds clarification.
Thanks a lot!!!
