IPA: /ˈstiːpli/
KK: /ˈstipli/
In a way that has a sharp incline or slope; at a high angle.
The road climbs steeply up the mountain.
Steeply is derived from the adjective "steep" (from Old English *stæpe*, meaning high or lofty) and the adverbial suffix "-ly" (meaning in a manner of). The word "steeply" describes an action done in a high or abrupt manner, often referring to a sharp incline or decline.
Think of something being 'high' or 'lofty' ('steep') and how it is done 'in a manner of' ('-ly'). This helps you remember that 'steeply' means to do something in a high or abrupt way.