noun, noun or participle which takes 'suru', transitive verb
cheering; shouts of encouragement; vocal support
Usually refers to audible encouragement for a person or team, especially in sports, performances, speeches, or public events. Very common in the phrase 声援を送る; 声援する is also possible but sounds more like written or report-style Japanese than 応援する.
沿道の人々がランナーに声援を送った。
People along the road cheered the runners on.
観
The spectators cheered the players on until the end.
温かい声援をありがとうございます。
Thank you for your warm support.