Crossword puzzle clue "hint at without saying"

Saying that often goes without saying

Hint at without saying

Standard with the lyrics "Your eyes are always saying / the things you're never saying"

Saying about power (and a hint to this puzzle's theme)

Answer to the riddle "What has rivers without water, forests without trees, and cities without houses?"

Hint (and a hint to this puzzle's theme)

"Mrs. Frisby and the Rats of ___" (classic 1971 children's book based on experiments at the National Insistute of Mental Health, hint hint)

Something your poetry teacher might assign you to write about a particularly inspirational poetry teacher you've had *hint* *hint