On the Spur of the Moment
On the Spur of the Moment 1100 Words You Need to Know Week 29 Day 1 with authentic examples, synonyms and antonyms for GRE, TOEFL & IELTS
impulsively and without thinking, on a momentary impulse, impetuously, on impulse, spontaneously, unprompted, extempore, unexpectedly, instinctively, in an improvised fashion, ad hoc
To say it is not a spur of the moment decision means that they put a lot of thought into their choice.
Source: https://hinative.com/
Antonyms: planned, scheduled