A fifteen letter word that contains the letters atragiclostnoun is congratulations!!!
Straightforward
Straightforward
smarty pants child
calorie
Both begin woth letter
A fifteen letter word that means easy is ultrasimplistic. Ultrasimplistic means easy to understand, deal with or use. It also means an ignorant, foolish or gullible person.
dieting
age before beauty
Defencelessness
i.e. is Latin - id est, so the 3 letter word is est
movie