# OpenVerbs Dictionary Antonyms

> OpenVerbs Dictionary Antonyms is a paid API for AI agents from dictionary.openverbs.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Returns antonyms (opposites) of an English word across all its senses, with optional part-of-speech filtering

## Facts

- Endpoint: POST https://dictionary.openverbs.com/v1/antonyms
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/openverbs-dictionary-antonyms-a2697589
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QmBaRifVoMLT2T8qlnh77

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability openverbs-dictionary-antonyms-a2697589 -d '<json body>'
```

Example prompt: What are the antonyms of the word 'brave' — only adjective forms?

## When to prefer this

Choose this endpoint when you need the semantic opposites of an English word, especially with part-of-speech control. Prefer it over a general thesaurus API when you specifically want antonyms (not synonyms or definitions), or when building vocabulary tools, writing assistants, NLP pipelines, or quiz generators that require opposite-word lookup with POS filtering.

## Known failure modes

- Unknown word returns found:false with HTTP 200 (not an error, check found flag before using results)
- No antonyms exist for the word in the given POS filter — returns empty list
- Misspelled or non-English input word returns found:false
- Empty string input rejected by schema validation (minLength:1)
- Invalid POS value outside enum rejected at input validation

## How this service works

Return the antonyms (opposites) of an English word, aggregated across all its senses. Optionally filter by part of speech. An unknown word returns found:false with a 200.

## Output

A JSON response containing a 'found' boolean and, when found, a list of antonym strings aggregated across all senses of the word. If a part-of-speech filter is applied, only antonyms from matching senses are returned. An unknown word returns found:false with HTTP 200.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "type": "object",
     "properties": {
      "word": {
       "type": "string",
       "minLength": 1,
       "description": "The word to look up."
      },
      "pos": {
       "type": "string",
       "enum": [
        "noun",
        "verb",
        "adjective",
        "adverb"
       ],
       "description": "Optional part-of-speech filter."
      }
     },
     "required": [
      "word"
     ],
     "additionalProperties": false
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openverbs-dictionary-antonyms-a2697589/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dictionary.openverbs.com](https://www.zero.xyz/host/dictionary.openverbs.com/llms.txt)