I'm a bit tired but I don't wanna forget to respond to you since you seem to ask in good faith. I'd say it depends on context, but generally a liberal is either someone who believes in liberal democracy (which includes conservatives, at least those who believe in elections and don't necessarily want fascism) or someone who believes in reformism as a possible way to transform a country (which includes well meaning people that we generally like, but we strongly disagree with in theory and praxis).

Don't get me wrong, we would love to be able to vote a better person and fix everything through electoralism, but we don't believe that's possible since 1) you generally need to appeal to corporations and billionaires to run a campaign to begin with, 2) even if you elected a perfect leader that cares about the people and is incorruptible, the US government would just remove them (both within the US itself and outside), 3) but if somehow your perfect leader endures, they'll die someday anyway, and liberal democracies are unable to keep the concessions for the workers long term, see at welfare deteriorating in many European countries. We generally see revolutions as necessary for meaningful progress, and we don't believe in liberal democracies actually representing the will of regular people, but rather the will of the rich, since elected people can just ignore their voters anyway in most cases, and propagandizing and lying to voters is extremely common.