Lead astray verb – Lead someone in the wrong direction or give someone wrong directions. Rat on and lead astray are semantically related. In some cases you can use "Rat on" instead a verb phrase "Lead astray".
Rat on verb – To give information (as to the authorities) about another's improper or unlawful activities. Lead astray and rat on are semantically related. Sometimes you can use "Lead astray" instead a verb "Rat on".