Related Clues:

• First person overseeing worker is determined
• These days a French lover is very hard
• Very hard computer programming language? Prayer is of no use!
• Firmly unchanging
• Unshakable (in an opinion)
• Inexorable
• "Goody Two Shoes" singer
• Impervious to appeals
• British New Wave singer
• Implacable
• Impervious to pleas or persuasion
• Insistent he was a new romantic in the 1980s
• Insistent girl should meet male model
• Unpersuadable
• Resolute drivers not disheartened about barrier