Dic: stand by, stand by someone or something

stand by:

• The Secretary of Defence has said that he would not stand by and let democracy be undermined.
• It was such a terrible fire that the firefighters had to stand by and let the fire burn itself out.
• Many bankers within the firm were outraged because, as in 1994, they stood by helpless as the firm's trading business took another severe blow. (slightly modulated from another source)

PHRASAL VERB | If you stand by and let something bad happen, you do not do anything to stop it. | to let something happen or to be unable to do anything to stop something from happening

• British and American warships are standing by to evacuate their citizens if necessary.
• We will be holding the auditions from nine o'clock tomorrow night so stand by for details.
• During the fireworks display, the fire department trucks stood by, in case something went up in flames.

PHRASAL VERB | If you are standing by, you are ready and waiting to provide help or to take action. | to be ready to be used if necessary.

stand by someone or something:

• I wouldn't break the law for a friend, but I would stand by her if she did.
• The decision has been made and I have got to stand by it.
• I think people admire the fact that she stands by her husband.
• At a news conference, he stood by his criticism of the government.

PHRASAL VERB | If you stand by someone, you continue to give them support, especially when they are in trouble.(= stick by) | If you stand by an earlier decision, promise, or statement, you continue to support it or keep it. (= stick by)

.... Cobuild, http://idioms.thefreedictionary.com/stand+by