中途半端にchuutohanpaniやるyaruくらいならkurainaraやらないyaranai方がましhougamashida
You may as well not do it at all than do it imperfectly.

© Based on JMdict, KANJIDIC2, and JMnedict, property of the Electronic Dictionary Research and Development Group, used in conformance with the Group's licence. Example sentences from the Tatoeba project (CC BY 2.0). Kanji stroke order data from the KanjiVG project by Ulrich Apel (CC BY-SA 3.0). See comprehensive list of data sources for more info.

Search other dictionaries for 中途半端にやるくらいなら、やらない方がましだ。:
Yahoo!辞書 / goo辞書 / alc.co.jp / Weblio / Wiktionary