импровизировать

extemporize; fake; hit off; fantasy; extemporise; phantasy; strike off; adlib (AlexP73); improvise; act on a hunch (ad_notam); speak impromptu (VLZ_58); make it up as one goes along (VLZ_58); think on one's feet (VLZ_58); take it as it comes (VLZ_58); speak off the cuff (VLZ_58); speak off the top of one's head (VLZ_58); busk it (VLZ_58); ride (о джазе); get creative (Taras); ad lib

amér., argot.

wing it

argot.

ad lib (в разговоре, чтении написанного текста или музыкальном исполнении); ad-lib (в разговоре, чтении написанного текста или музыкальном исполнении); wing it (в любой области)

figur.

play by ear (Andrey Truhachev)

idiom.

make up as goes along (None of us really knew how to play the game, so we just made it up as we went along. VLZ_58); play by the ear (george serebryakov)

inform.

ad-lib; wing (winging Eugenev); freestyle (глагол) Lily Snape); rift (No direct quotes here, just rifting. joyand); play something by ear (to do something without special preparation: He decided to remain calm and play it by ear. Snowklkl)

makar.

strike; ad-lib a joke; do an improvisation; improvise on

makar., inform., latin.

ad-lib (обыкн на сцене или по радио)

makar., latin.

ad-librium (обыкн на сцене или по радио)

musiq., amér.

ride (в джазе)

musiq., jarg.

jam (в джазе)

musiq., makar.

vamp (особ. аккомпанемент)