As in Dennis the Menace, the word defines itself. This little bugger is a menace to his neighbor. Causing havoc and turmoil .
Menace is to frighten or intimidate.
The menacing figure loomed in the shadows, sending shivers down my spine.
The word 'menacing' is a noun form, a gerund, the present participle of the verb to menace.The word menace is a noun form, a word for a possible danger; a threat; an act of threatening.The noun forms for the verb to menace are menacer (one who menaces) and the gerund, menacing.
menacing
The girl wore a menacing expression on her face.
Baleful means something that produces harm or injury, so definitely menacing!
Evil, Threatening, Menacing, Hostile, Etc.
The word menace is a noun. The plural is menaces.
In your sentence, the word 'grumbling' is the main verb('was' is the auxiliary verb).
Sharp, acute, bright, penetrative, piercing, menacing, savvy.
The word menace can be used as a noun or verb. Menacing literally means to cause harm or malace to another. Synonyms include threaten, risk, and danger.
"He looked at me with menacing eyes." "The menacing wolf bared his teeth at me snarling."
" The hero sprang into action to save the town from the menacing villain."