What is the meaning of hold back?

verb

• Hold back, as of a danger or an enemy; check the expansion or influence of.
  • usage: "Arrest the downward trend"; "Check the growth of communism in South East Asia"; "Contain the rebel movement"; "Turn back the tide of communism"
  • synonyms: check, turn back, arrest, stop, contain
• Keep under control; keep in check.
  • usage: "suppress a smile"; "Keep your temper"; "keep your cool"
  • synonyms: restrain, keep, keep back
• Refrain from doing.
  • usage: "she forbore a snicker"
  • synonyms: forbear
• Wait before acting.
  • usage: "the scientists held off announcing their results until they repeated the experiment"
  • synonyms: wait, hold off
• Secure and keep for possible future use or application.
  • usage: "The landlord retained the security deposit"; "I reserve the right to disagree"
  • synonyms: retain, hold, keep back
• Hold back; keep from being perceived by others.
  • usage: "She conceals her anger well"
  • synonyms: conceal, hold in