muchísimo / muchísima (adjective, adverb)

Frequency star
  1. very much, a great deal, a lot
  2. very much (as intensifier before nouns, meaning “a great deal of”)

Me gusta muchísimo esta tarta de zanahoria, ¿inventaste la receta?

I really love this carrot cake you made, did you make up the recipe?

Me afectó muchísimo la noticia sobre el zorro atropellado.

The news about the fox getting run over really affected me.

Estos zapatos nuevos me aprietan muchísimo en los dedos.

These new shoes are really tight on my toes.

Subir tantas escaleras siempre me cansa muchísimo.

Climbing so many stairs always tires me out a lot.

Me duele muchísimo la espalda después de mudarme de casa.

My back hurts a lot after moving house.