Euphemism – substitute strong word for milder one
Euphemism is the substitution of a milder, vaguer word for one considered to be offensive or unpleasant.
“That’s just a youth’s mist.” (euphemism).
“No, it’s a fart!”
“They are academically challenged” is a euphemism for stupid.
“Adult entertainment” instead of pornography.
“Between jobs” instead of unemployed.