What it means
Soft and squishy like overcooked vegetables, and so, of feelings, gooey and over-sentimental. A mushy film is a tearjerker, a mushy text is the kind that makes you cringe and grin at once. The word does double duty for soggy peas and soggy hearts alike.
Usage examples
"The ending got really mushy, everyone hugging in the rain, but I will admit I had something in my eye."
"Granddad got proper mushy at the wedding toast, kept patting people on the shoulder and telling them they were lovely, my gran handed him a tissue with a wink."
"I cannot rewatch that scene without going mushy, it is the bit where the dog finds the owner at the train station, and somehow I always have a leak in the eye."
"Don't go all mushy on me just because the old couple in the advert started dancing in the kitchen."
"Her birthday post was dead mushy, full of soulmate chat and baby photos, but fair play, it was kind of sweet."
Where it comes from
It comes from mush, a word for a soft pulpy mass that’s been around in English for centuries. Mushy first stuck to food and texture, then slid over to emotions by the 1800s. That’s why it still works for both overcooked peas and over-the-top sentimental vibes.