Rigorous and vigorous can both describe something challenging, but they emphasize different qualities.
Rigorous means thorough, exact, and careful, often because strict standards or procedures are followed. A rigorous investigation examines evidence closely. Rigorous testing checks a product under carefully controlled conditions.
The word can also describe something demanding that requires discipline or sustained effort. A rigorous course may involve difficult assignments, frequent assessments, and high academic standards.
Vigorous describes strong energy, active movement, or force. Vigorous exercise makes the body work hard. A vigorous plant grows strongly and appears healthy. The word can also describe forceful activity that is not physical, such as vigorous debate or vigorous opposition.
- Rigorous: The researchers used rigorous methods to verify the results.
- Vigorous: We went for a vigorous walk along the coast.
- Rigorous: The dancers followed a rigorous training program.
- Vigorous: The committee engaged in vigorous debate.
Sometimes both words can fit the same noun but change the emphasis. Rigorous training suggests a strict, demanding program. Vigorous training emphasizes energetic or physically forceful activity. When choosing between them, ask whether the main idea is careful standards and discipline or energy and force.