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un·flap·pa·ble /ˌʌnˈflæpəbəl/ adjective

 

[more unflappable; most unflappable] : not easily upset : unusually calm in difficult situations
▪ He has a reputation for being unflappable.

 

 

²hamstring verb

hamstrings; hamstrung /-ˌstrʌŋ/ hamstring·ing

 

[+ obj] : to damage or ruin the force or effectiveness of (something or someone)
▪ The mayor tried to hamstring our efforts by cutting the budget. ▪ The company claims it is being hamstrung by government regulations.