Military-Style, Extreme Exercise Class
Puzzle 15 of Cold Places Easy Pack
Question is: Military-Style, Extreme Exercise Class
and the answer is: BOOTCAMP
Word Meaning:
BOOT CAMP — (chiefly Canada, US, military, colloquial) An initial, basic indoctrination, physical fitness training and basic instruction in service-related subjects for new recruits in the armed forces (army, Air Force, navy and Marine Corps).
Definitions from Wiktionary.