He doesn't work, counting on his parents' inheritance.
At old-time banquets, they played guessing games.
Standard kanji spelling; the reading あてこと is also possible but less common.
Mixed kana spelling that clarifies the reading; useful for learners.
Compound of 当て (ate, 'guess, expectation') + 事 (koto, 'thing, matter'). The exact historical derivation is uncertain.