What is the meaning of frustrating?

verb

• Hinder or prevent (the efforts, plans, or desires) of.
  • usage: "What ultimately frustrated every challenger was Ruth's amazing September surge"; "foil your opponent"
  • synonyms: thwart, queer, spoil, scotch, foil, cross, frustrate, baffle, bilk
• Treat cruelly.
  • usage: "The children tormented the stuttering teacher"
  • synonyms: torment, rag, bedevil, crucify, dun, frustrate

adjective

• Discouraging by hindering.
• Preventing realization or attainment of a desire.
  • synonyms: frustrative, thwarting