Possible Clues:

• Repressed
• Reserved yet looking very fit
• Uncommunicative book put out — end is awful
• Restrained individual behind leading politicians
• Repressed, although more vigorous
• Like coat securely put on, or pulled off
• Taciturn, yet concluded satisfactorily
• Uncommunicative, but made more vigorous
• Uncommunicative one so ready to act unfortunately put on debut
• Tight-lipped and presumably lacking zip!