Having the power to move heavy weights or perform other physically demanding tasks. Able to withstand great force or pressure. (of light) very intense. Denoting a class of verbs in Germanic languages that form the past tense and past participle by a change of vowel within the stem rather than by addition of a suffix (e.g., swim , swam , swum ) ; contrasted with weak. Of, relating to, or denoting the strongest of the known kinds of force between particles, which acts between nucleons and other hadrons when closer than about 10 −13 cm (so binding protons in a nucleus despite the repulsion due to their charge), and which conserves strangeness, parity, and isospin.