straining
adj.showing that someone is trying very hard to do something, often with a lot of physical or mental effort. It describes a look or sound that is not relaxed because of this struggle.
adj.characterised by intense effort or exertion; appearing forced or unnatural due to the difficulty of the task. Often used to describe facial expressions, voices, or physical movements that lack ease.
“He spoke with a straining voice as he tried to lift the heavy box.”
“The athlete's straining muscles were visible as she pushed through the final meters of the race.”
“The diplomat maintained a straining smile throughout the tense negotiations, clearly struggling to hide his growing frustration with the lack of progress.”
Often used attributively before a noun to describe physical or emotional effort.
“Since then, the virus has spread rapidly, straining government responses.”
“My much-atrophied Python muscles were already straining and would absolutely not be able to meet this challenge.”