Why tiring, not tiresome?

English as a Second Language English Teacher Explanations (ESL Tests)
1

Hi, Alan,

I don’t understand why tiresome will not fit in here? When can I use this word?

Regards,
Elena
Test No. [color=blue]errors/advan-1 “Give me the bill”, question 3

Working all day long in financial services can be a very tired occupation.

(a) all day
(b) in
(c) services
(d) tired

Test No. [color=blue]errors/advan-1 “Give me the bill”, answer 3

Working all day long in financial services can be a very tiring occupation.

Correct entry: tiring
The error was: (d) tired

You have [color=green]found the error but your entry is [color=red]incorrect.
Working all day long in financial services can be a very tiresome occupation.

2

Hi,

Thanks for your question. Here in this test you need ‘tiring’ because it’s a synonym for ‘exhausting’ in other words ‘tiring’ means ‘making you feel tired’. Keeping young children happy during the school summer holidays is a tiring experience for parents. ‘Tiresome’ on the other hand means ‘irritating’. For example my surname is TOWNEND but most people spell it wrong and say or write ‘TOWNSEND’ and for me that is tiresome or irritating.
Alan