ramp has 5 distinct synonyms spread across 3 of its 8 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
furnish with a ramp
“The ramped auditorium”
Synonyms, antonyms and the broader and narrower relations for ramp come from Princeton University’s WordNet. Full sources and licences.
be rampant
“the lion is rampant in this heraldic depiction”
creep up -- used especially of plants
“The roses ramped over the wall”
stand with arms or forelegs raised, as if menacing
an inclined surface connecting two levels
North American perennial having a slender bulb and whitish flowers
a movable staircase that passengers use to board or leave an aircraft