積む (tsumu) conjugation
to pile up, to stack
積む (つむ, tsumu) is a godan verb. Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば. 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 | 積む tsumu | 積みます tsumimasu | The form you look up. Also the casual present and future. |
| Plain negative | 積まない tsumanai | 積みません tsumimasen | “doesn’t / won’t”. From here it conjugates like an i-adjective. |
| Plain past | 積んだ tsunda | 積みました tsumimashita | The casual past — same ending as the te-form, with た/だ. |
| Plain past negative | 積まなかった tsumanakatta | 積みませんでした tsumimasendeshita | “didn’t”. The negative past, still i-adjective-shaped. |
| Te-form | 積んで tsunde | — | The connector: requests, linking clauses, ~ている. |
| Progressive (~ている) | 積んでいる tsundeiru | 積んでいます tsundeimasu | “is ~ing”, or an ongoing resulting state. |
| Desire (~たい) | 積みたい tsumitai | 積みたいです tsumitaidesu | “want to ~”. Behaves as an i-adjective. |
| Volitional | 積もう tsumou | 積みましょう tsumimashou | “let’s ~” / “I think I’ll ~”. |
| Potential | 積める tsumeru | 積めます tsumemasu | “can ~”. What you could do; the object often takes が. |
| Passive | 積まれる tsumareru | 積まれます tsumaremasu | “is ~ed”. Also the honorific and the suffering passive. |
| Causative | 積ませる tsumaseru | 積ませます tsumasemasu | Make or let someone do it. |
| Causative-passive | 積まされる tsumasareru | 積まされます tsumasaremasu | Be made to do it — the long one. |
| Imperative | 積め tsume | 積んでください tsundekudasai | Blunt order. Use ~てください in real life. |
| Prohibitive | 積むな tsumuna | — | “don’t!” — dictionary form + な. |
| Conditional (~ば) | 積めば tsumeba | — | “if ~”. General rules and hypotheticals. |
| Conditional (~たら) | 積んだら tsundara | — | “if / when ~”. The everyday conditional. |
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Why it conjugates this way
Godan verbs change their final kana up and down its column of the kana chart — the a-row for negatives, the i-row before ます, the e-row for potential and ば.
See the full rules on the verb conjugation guide.