Apace and Double quick

Apace adverb - With great speed.

Double quick and apace are semantically related In some cases you can replace phrase "Double quick" with "Apace", this terms are similar.

Double quick adverb - At a faster speed.

Apace and double quick are semantically related in very fast topic. Sometimes you can use "Apace" instead an adverb phrase "Double quick", if it concerns topics such as with great speed.