Antonyms of adj unflagging

2 senses of unflagging

Sense 1
indefatigable, tireless, unflagging, unwearying -- (showing sustained enthusiastic action with unflagging vitality; "an indefatigable advocate of equal rights"; "a tireless worker"; "unflagging pursuit of excellence")

INDIRECT (VIA energetic) -> lethargic, unenrgetic -- (deficient in alertness or activity; "bullfrogs became lethargic with the first cold nights")

Sense 2
unfailing, unflagging -- (unceasing; "unfailing loyalty"; "unfailing good spirits"; "unflagging courtesy")

INDIRECT (VIA constant) -> inconstant -- (likely to change frequently often without apparent or cogent reason; variable; "inconstant affections"; "an inconstant lover"; "swear not by...the inconstant moon"- Shakespeare)

Similarity of adj unflagging

2 senses of unflagging

Sense 1
indefatigable, tireless, unflagging, unwearying -- (showing sustained enthusiastic action with unflagging vitality; "an indefatigable advocate of equal rights"; "a tireless worker"; "unflagging pursuit of excellence")
       => energetic (vs. lethargic) -- (possessing or exerting or displaying energy; "an energetic fund raiser for the college"; "an energetic group of hikers"; "it caused an energetic chemical reaction")

Sense 2
unfailing, unflagging -- (unceasing; "unfailing loyalty"; "unfailing good spirits"; "unflagging courtesy")
       => constant (vs. inconstant) -- (steadfast in purpose or devotion or affection; "a man constant in adherence to his ideals"; "a constant lover"; "constant as the northern star")