Around 1400, the word tepid appeared in the late Middle English period (1150-1500).  Tepid is borrowed from Latin and evolved from the Latin tepidus, an adjective meaning “lukewarm,” which before that came about from the Latin tepere, a verb meaning “to be warm.” Tepid people or things are lukewarm or lacking in enthusiasm or emotion. 

Examples of tepid in a sentence:  
"The audience gave a tepid applause after the performance." 
"She bent her mouth to the tap and drank the tepid water." 
"The company's response to the crisis was tepid, and they failed to take decisive action." 
"The new movie received a tepid reception from critics." 
"The soup was tepid and not hot enough to enjoy." 
"The views expressed have ranged from tepid enthusiasm to cautious pessimism."
"To me they appeared somewhat tepid and over-tinted with caution." 
"No condemnation of this illegality had come from anyone, except the rather tepid words of condemnation that had to be squeezed out today." 

In the last week our dear @Myr has had the temerity to scuttle fine philosophical words like epicurean and deluge us with images of ribald behaviour while pretending to remain tepid and aloof from the repercussions. I think I need to reach for my shillelagh.   

Just the facts:

TEPID Definition & Meaning - Merriam-Webster