a sundecker is a nice, juicy pile of excrement left on the chest of sunbathing women on any type of deck.

Likewise, a sundecker can also be referred to any individual who can accurately take a poop from a lofty deck (in a mandatory, hot day) and ensure it hits an unsuspecting (or suspecting) victim below with total, fecal precision.

yup. it is a noun, a verb, and can be used in any sense that degrades male or female good standing with fecal matter and/or can be laughed at in a complete lack of taste.
1. Two women are sun bathing on their back deck. A man sneaks up, drops his trousers in the afternoon's sweltering heat and releases a growler that coils up like fountain yogurt on one of the woman's chest. Relieved, he runs off as the other woman wakes up after smelling something cooking in the sun and screams "OH, MY GOD! YOU HAVE A SUNDECKER ROASTING ON YOUR CHEST!"

2. A frat boy feels a rumble in his tummy. He runs out to the second story deck, drops his trousers, and sits on the railing in reverse: his butt hanging over the people below. Sweating and squeezing in the hot afternoon, he drops a sundecker on one of the pledges below.
by TripNixon July 28, 2013
Get the sundecker mug.
A phrase used to express extreme disapproval with a certain scenario/situation
“If I lose this hand of poker, I swear I’m gonna swan dive off the sundeck
“I can’t believe I went all in on pocket two’s and lost all my chips in poker- now I’m gonna go swan dive off the sundeck”
by Mdrzik26 December 19, 2019
Get the Swan dive off the sundeck mug.