kraftvoll
powerful
Full of physical strength, energy, or force.
Der Schmied schlug mit einem kraftvollen Hieb auf das glühende Eisen.
The blacksmith struck the glowing iron with a powerful blow.

powerful
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powerful
Full of physical strength, energy, or force.
Der Schmied schlug mit einem kraftvollen Hieb auf das glühende Eisen.
The blacksmith struck the glowing iron with a powerful blow.

The word is built simply: it consists of the noun 'die Kraft' (strength/power) and the ending '-voll' (-ful). So it literally means 'full of strength'.
Mit einer kraftvollen Anstrengung schaffte er es über die Ziellinie.
With a powerful effort, he made it across the finish line.
In relation to physical strength, 'kraftvoll' (powerful) is often combined with nouns such as 'Bewegung' (movement), 'Schlag' (blow/punch), 'Tritt' (kick), or 'Sportler' (athlete).
Der Boxer landete einen kraftvollen Treffer.
The boxer landed a powerful hit.
When it comes to expressiveness, 'kraftvoll' (powerful) often describes nouns such as 'Stimme' (voice), 'Rede' (speech), 'Sprache' (language), 'Musik' (music), or 'Bild' (picture, in the sense of a work of art).
Der Dirigent führte das Orchester zu einer kraftvollen Interpretation des Stücks.
The conductor led the orchestra in a powerful interpretation of the piece.
For sensory impressions, 'kraftvoll' (strong/intense) describes intense aromas, tastes, or colors. Typical nouns are 'Geschmack' (taste), 'Aroma' (aroma), 'Duft' (scent), or 'Farbe' (color).
Der Käse hat einen sehr kraftvollen Geschmack.
The cheese has a very strong taste.
strong
'stark' and 'kraftvoll' can both express that there is a lot of strength, energy, or effect. 'stark' is very general and fits many situations: for people, wind, pain, coffee, or feelings. 'kraftvoll' sounds a bit more vivid and emphasizes active force or strong expression. For example, people say 'eine kraftvolle Stimme' (a powerful voice) or 'eine kraftvolle Bewegung' (a powerful movement). For simple everyday statements, 'stark' is often more natural; 'kraftvoll' fits better when something seems energetic, effective, or expressive.

Die Sängerin hatte eine kraftvolle Stimme, und alle hörten sofort zu.
The singer had a powerful voice, and everyone immediately listened.
Nach dem Gewitter war der Wind noch immer sehr stark.
After the storm, the wind was still very strong.