Why does 减弱 (lit. "reduce weak") mean "to weaken"? 减弱 (jiǎn​ruò)
CC-CEDICT: to weaken / to fall off

I find this counter-intuitive, since we have:

减
CC-CEDICT: to lower / to decrease / to reduce / to subtract / to diminish
弱
CC-CEDICT: weak / feeble / young / inferior / (following a decimal or fraction) slightly less than

It seems like 减弱 should mean &quot;reduce weakness&quot; and therefore &quot;strengthen&quot;, but it means the opposite.  For comparison, 减肥 means &quot;lose weight&quot;.
Question: Why does 减弱 (lit. &quot;reduce weak&quot;) mean &quot;to weaken&quot;?
肥 in 减肥 is a noun; 弱 in 减弱 is an adjective
减肥 = 减(少)肥(胖) = reduce obesity
减弱 = 减(低)(變)弱  decrease and weaken
Example:
&quot;颱風减弱&quot; = &quot;颱風(威力)减(低)(變)弱&quot; = &quot;Typhoon (power) decreases and weakens&quot;
The power decreased and the typhoon became weaker