Hateful
い adjective
憎む is "to hate" - the adjective version is hateful.
The reading comes from 憎む as well, so if you know this no need to show any hate towards this vocab.
候補者のコウイチ氏は、大統領候補討論会の前、憎らしいほど落ち着いていました。
Candidate Koichi was provokingly cool before the presidential debate.