Wiktionary
extemporising
vb. (present participle of extemporise English)
Usage examples of "extemporising".
Spread on the jury foremast these enabled them to get the Pretty Jane before the trade wind, to creep along at a mile an hour while they set to work on extemporising aftersails that doubled her speed.
This was all very vexing, but it was responding well, playing it by the book where possible and extemporising sensibly but with all due urgency where it had to.