Learn how to say Deficient correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word deficient:
1not having enough of a specified quality or ingredient:
this diet is deficient in vitamin B
insufficient or inadequate:
the documentary evidence is deficient
2 (also mentally deficient) offensive having mental disabilities.
late 16th century (originally in the theological phrase deficient cause, denoting a failure or deficiency that has a particular consequence): from Latin deficient- ‘failing’, from the verb deficere (see defect1)