no strings attached vs unreserved

no strings attached

adj

  • Characterized by an absence of conditions or obligations. 

adv

  • Without conditions or obligations; without a catch. 

unreserved

adj

  • Not reserved, without reservations. 

  • Not booked in advance. 

How often have the words no strings attached and unreserved occurred in a corpus of books? (source: Google Ngram Viewer )