At once and Nontraditional

At once adverb - Without delay or hesitation; with no time intervening.

Nontraditional and at once are semantically related. In some cases you can use "Nontraditional" instead an adjective phrase "At once".

Nontraditional adjective - Not bound by traditional ways or beliefs.

At once and nontraditional are semantically related. Sometimes you can use "At once" instead an adjective "Nontraditional".