1
general::
Phrase(s): touch someone or something off
Fig. to ignite or excite someone or something; to excite anger or chaos. • She is very excitable. The slightest thing will touch her off. • The appearance of the fox touched off a furor in the henhouse.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
1. Cause to explode or fire; also, initiate, trigger. For example, The boys touched off a whole line of firecrackers, or These disclosures will touch off a public uproar. This idiom comes from early firearms, which were set off by putting a light to the touch-hole. Its figurative use dates from the late 1800s. 2. Depict very precisely, as in He touched off Teddy Roosevelt as well as it's ever been done. [Mid-1700s]
American Heritage Idioms