(of the thyroid or adrenal glands) not functioning at full capacity
underactive in American English
(ˌundərˈæktɪv)
adjective
insufficiently active
an underactive thyroid gland
Derived forms
underactivityunderactiveness
noun
Word origin
[1955–60; under- + active]This word is first recorded in the period 1955–60. Other words that entered Englishat around the same time include: backgrounder, cassette, geodesic dome, new wave, softwareunder- is a prefixal use of under, as to indicate place or situation below or beneath (underbrush; undertow); lower in grade or dignity (undersheriff; understudy); of lesser degree, extent, or amount (undersized); or insufficiency (underfeed)
Examples of 'underactive' in a sentence
underactive
Other causes include excessive typing, arthritis or an underactive thyroid.
The Sun (2010)
Like me, you can have an over as well as underactive thyroid.
The Sun (2011)
With the tiredness it pointed to an underactive thyroid.
The Sun (2011)
In which case you'll miss the diagnosis of depression or an underactive thyroid.
Times, Sunday Times (2008)
An overactive thyroid causes weight loss and an underactive thyroid causes weight gain.
The Sun (2017)
Patients with underactive thyroids don't have to pay for any of their pills.
The Sun (2008)
Or an underactive thyroid because your mum had the same and you can't slim?
The Sun (2008)
Sadly, she has medical problems with an underactive thyroid.
The Sun (2016)
It's ever so slightly underactive but only by a very small fraction.
The Sun (2012)
Another sign of an underactive or overactive thyroid is hair loss.