Sentence:  ... he remembered how terse and <WSD>unexcitable</WSD> the jeweller was, so different from those gem-dealers who, meeting with each other on the pavements at Hatton Garden, could not contain for two seconds their business verve, nor refrain from displaying there and then their tiny precious wares, produced out of waistcoat pockets and wrapped in tissue paper. 
Meaning of the word marked with <WSD> tags:  Not excitable, not easily excited.