underactive

[ uhn-der-ak-tiv ]
/ ˌʌn dərˈæk tɪv /

adjective

insufficiently active: an underactive thyroid gland.

Origin of underactive

First recorded in 1955–60; under- + active

OTHER WORDS FROM underactive

un·der·ac·tiv·i·ty, un·der·ac·tive·ness, noun
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Examples from the Web for underactive

British Dictionary definitions for underactive

underactive
/ (ˌʌndərˈæktɪv) /

adjective

(of the thyroid or adrenal glands) not functioning at full capacity
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012