Dictionary.com
Thesaurus.com

gentle giant

American  
[jen-tl jahy-uhnt] / ˈdʒɛn tl ˈdʒaɪ ənt /

noun

  1. a person or animal that may seem intimidating because of great size, strength, talent, influence, etc., but is surprisingly friendly and not aggressive or threatening.

    Don’t be afraid of my huge dog—St. Bernards are gentle giants.

    A towering figure among scientists, she was a gentle giant who made others feel at home as they learned the profession.

Etymology

Origin of gentle giant

First recorded in 1810–20

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.