Inadequate to implies that something is lacking in its ability to perform a task or meet a certain standard. There are many synonyms for this phrase, including insufficient, deficient, unsatisfactory, substandard, inferior, below par, lacking, wanting, incompetent, incapable, feeble, weak, limited, and imperfect. Each of these terms describes a situation where something falls short of what is expected or required. Whether it is a product, service, or person, using synonyms for inadequate to helps to convey the message that something is not up to par and requires improvement or further attention.