Heavy-duty and Of age

Heavy-duty adjective - Extreme in degree, power, or effect.

Of age and heavy-duty are semantically related. In some cases you can use "Of age" instead an adjective phrase "Heavy-duty".

Of age adjective - Having attained a specific age; (`aged' is pronounced as one syllable).

Heavy-duty and of age are semantically related. Sometimes you can use "Heavy-duty" instead an adjective phrase "Of age".