# OpenVerbs Dictionary Synonyms API

> OpenVerbs Dictionary Synonyms API 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 synonyms of an English word aggregated across all its senses, with optional part-of-speech filtering

## Facts

- Endpoint: POST https://dictionary.openverbs.com/v1/synonyms
- 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-synonyms-api-48ab4f53
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ng5nW-6AaYZreWpq6gJX-

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-synonyms-api-48ab4f53 -d '<json body>'
```

Example prompt: What are the synonyms for the word 'eloquent' as an adjective? I want all the alternatives I can use in my writing.

## When to prefer this

Choose this endpoint when you need English synonym lookup with sense aggregation and optional POS filtering, especially in an agentic pipeline where you pay per call with USDC via x402. Prefer it over free thesaurus APIs when you need reliable JSON output, POS filtering, and per-call micropayment billing. Its sibling antonym and definition endpoints on the same host allow building a full lexical enrichment pipeline.

## Known failure modes

- Unknown word returns found:false with HTTP 200 rather than an error
- Words with no synonyms in the dictionary return an empty synonyms array
- Misspelled words may return found:false
- Part-of-speech filter may reduce synonym count significantly or return empty results if the word is not used in that POS
- Payment failure (x402) if insufficient USDC balance

## How this service works

Return the synonyms 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 object indicating whether the word was found (found: true/false), and if found, a list of synonyms aggregated across all senses of the word. Results may be scoped to a specific part of speech (noun, verb, adjective, adverb) if the optional pos filter is provided. An unknown word returns found:false with HTTP 200.

## Request schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/openverbs-dictionary-synonyms-api-48ab4f53/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)