A household chore that is decreasing (7)
I believe the answer is:
I believe this clue is a double definition.
'a household chore' is the first definition.
(I've seen this before)
'is decreasing' is the second definition.
(de-creasing: removing creases)
'that' is the link.
(Other definitions for ironing that I've seen before include "Household chore" , "Pressing clothes" , "Household task" , "A pressing engagement" , "A housework chore" .)