用いる (mochiiru) conjugation
to use, to make use of
用いる (もちいる, mochiiru) is an ichidan verb. Ichidan verbs are the tidy ones: drop the final る and add the ending. Nothing inside the word ever changes. Every form below is tappable — hear it, then say it back.
Conjugation table
| Form | Plain (casual) | Polite (~ます) | When you use it |
|---|---|---|---|
| Dictionary / plain | 用いる mochiiru | 用います mochiimasu | The form you look up. Also the casual present and future. |
| Plain negative | 用いない mochiinai | 用いません mochiimasen | “doesn’t / won’t”. From here it conjugates like an i-adjective. |
| Plain past | 用いた mochiita | 用いました mochiimashita | The casual past — same ending as the te-form, with た/だ. |
| Plain past negative | 用いなかった mochiinakatta | 用いませんでした mochiimasendeshita | “didn’t”. The negative past, still i-adjective-shaped. |
| Te-form | 用いて mochiite | — | The connector: requests, linking clauses, ~ている. |
| Progressive (~ている) | 用いている mochiiteiru | 用いています mochiiteimasu | “is ~ing”, or an ongoing resulting state. |
| Desire (~たい) | 用いたい mochiitai | 用いたいです mochiitaidesu | “want to ~”. Behaves as an i-adjective. |
| Volitional | 用いよう mochiiyou | 用いましょう mochiimashou | “let’s ~” / “I think I’ll ~”. |
| Potential | 用いられる mochiirareru | 用いられます mochiiraremasu | “can ~”. What you could do; the object often takes が. |
| Passive | 用いられる mochiirareru | 用いられます mochiiraremasu | “is ~ed”. Also the honorific and the suffering passive. |
| Causative | 用いさせる mochiisaseru | 用いさせます mochiisasemasu | Make or let someone do it. |
| Causative-passive | 用いさせられる mochiisaserareru | 用いさせられます mochiisaseraremasu | Be made to do it — the long one. |
| Imperative | 用いろ mochiiro | 用いてください mochiitekudasai | Blunt order. Use ~てください in real life. |
| Prohibitive | 用いるな mochiiruna | — | “don’t!” — dictionary form + な. |
| Conditional (~ば) | 用いれば mochiireba | — | “if ~”. General rules and hypotheticals. |
| Conditional (~たら) | 用いたら mochiitara | — | “if / when ~”. The everyday conditional. |
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Why it conjugates this way
Ichidan verbs are the tidy ones: drop the final る and add the ending. Nothing inside the word ever changes.
See the full rules on the verb conjugation guide.