Helvetian/helʹveesh(ə)n/ adj

• hard as nails
• hardback
• hardball
• hard-bitten
• hardboard
• hard-boil
• hard-boiled
• hard by
• hard case
• hard cash
• hard coal
• hard copy
• hard core
• hardcore
• hard-core
• hard disk
• hard drive
• harden
• hard going said
• hard hat
• hardhead
• hardheaded
• hardhearted
• hard-hitting
• hardihood