えんりょのかたまり

that one last piece of food at the table that everyone refuses to eat because they don't want to be the rude one.

Word type: 

Kanji: 

遠慮の塊

Standard: 

のこりもの(たべもの)

Standard kanji: 

残り物(食べ物)

Example: 

だれかこのえんりょのかたまり食べてぇな。
Will someone just finish this last one please?

Commentary: 

"えんりょ" means to reserve.
"かたまり" means lump.
The literary means of "えんりょのかたまり" is a lump of reserve.