Less lenient

• Less of a picnic
• More puzzling, as a crossword
• More demanding
• More steely
• Not so easy
• Taking more time, probably, as a test
• "Pull more!"
• Higher on the Mohs scale

Wiktionary Word definitions in Wiktionary
Etymology 1 a. (en-comparative of: hard) Etymology 2 n. (context South Africa English) Any of several species of mullet often used to make bokkoms.

WordNet Word definitions in WordNet
See hard