|  | 
Definition of Portentously
1. Adverb. In a portentous manner. "Portentously, the engines began to roll" 
Partainyms: Portentous
Definition of Portentously
1. Adverb. In an ominous manner. ¹
2. Adverb. In a pompous manner. ¹
¹ Source: wiktionary.com
Definition of Portentously
1. [adv]



