Noun
(uncountable, sports) Backspin.
(countable, sports) A shot using backspin.
Source: en.wiktionary.org;Underspin Reel Operation A lever or trigger is grasped or rotated (usually by the forefinger) and this action suspends the line in place. Source: Internet
Underspin reel Underspin reels or Triggerspin reels are spin cast reels in which the reel is mounted underneath a standard spinning rod. Source: Internet