high, lofty, towering
craggy, jagged, rocky, sharp
snow-capped, snow-covered, snowy
distant
mountain

climb, conquer, scale

loom, rise, tower
We looked up at the rocky peaks towering above us.

on a/the peak
climbers on the distant mountain peaks

all-time
The share index rose to a new all-time peak of 2112.

seasonal
summer, winter, etc.
The influx of tourists has reached its summer peak.

sharp
The graph shows two very sharp price peaks.

rise to, rise towards/toward
Production is rising back towards/toward its 1999 peak.

hit, reach
fall below, fall from, pass
be past
Her performance is just past its peak.

hours, period, season, time, year
demand
at times of peak demand

rate
peak-rate phone calls

level
efficiency, performance
The engine is tuned to peak efficiency.

fitness (esp. BrE), form

at a/the/your peak
The crisis was now at its peak.
At his peak he was the best player in the world.

peak of
She is at the peak of her popularity.
The party's numbers reached a peak of 40 000 in 2001.

in peak condition
You want your hair to look in peak condition.

peaks and troughs
Economic life moves in cycles of peaks and troughs.