English for Today by Ganiu Abisoye Bamgbose (Dr GAB)
DO NOT SEPARATE THEM
There is no ~gain saying~ you won’t leave his house (nonstandard).
There is no gainsaying you won’t leave his house.
There hasn’t been ~rain fall~ in a while (nonstandard).
There hasn’t been rainfall in a while (standard).
He was here yesterday, ~not withstanding~ the rainfall (nonstandard).
He was here yesterday, notwithstanding the rainfall (standard).
Note that some other words can either be written as a single word or be separated:
Stomach ache ✔
Stomachache ✔
GAB
