drill has 7 distinct synonyms spread across 4 of its 9 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.
make a hole, especially with a pointed power or hand tool
“don't drill here, there's a gas pipe”
train in the military, e.g., in the use of weapons
undergo military training or do military exercises
a tool with a sharp point and cutting edges for making holes in hard materials (usually rotating rapidly or by repeated blows)
similar to the mandrill but smaller and less brightly colored
systematic training by multiple repetitions
“practice makes perfect”
(military) the training of soldiers to march (as in ceremonial parades) or to perform the manual of arms
Synonyms, antonyms and the broader and narrower relations for drill come from Princeton University’s WordNet. Full sources and licences.