The phrase "well constructed" refers to something that has been carefully and skillfully built or put together. Some synonyms for this phrase include "well-crafted," "well-built," "sturdy," "solidly constructed," "sound," "fabricated," and "assembled with care." Other synonyms may include "durable," "well-engineered," "well-formed," "precise," and "meticulously constructed." These words all suggest that a high level of attention to detail, skill, and care went into the creation of the object being described. Whether it's a building, a piece of furniture, or a piece of writing, something that is well constructed is generally considered to be of high quality and reliable.