Yes — but the combined work must be released under the more restrictive license.
GNU Lesser GPL v2.1 is a file-level (or library-level) copyleft license. You can include GNU Lesser GPL v2.1 files in a Do What The F*ck You Want To Public License project; the GNU Lesser GPL v2.1 files retain their copyleft obligation (changes must be released), while the project at large can stay Do What The F*ck You Want To Public License. Keep file boundaries clear.
| License | Family | Patent grant |
|---|---|---|
| GNU Lesser GPL v2.1 (LGPL-2.1) | weak-copyleft | No (implicit at most) |
| Do What The F*ck You Want To Public License (WTFPL) | permissive | No (implicit at most) |
GNU Lesser GPL v2.1: Library copyleft: dynamic linking permitted from non-LGPL code without triggering full copyleft.
Do What The F*ck You Want To Public License: Effectively public-domain; widely used informally but considered legally weak by some lawyers.
If you found this page because you're trying to figure out whether shipping a particular dependency is safe, the answer above is a starting point — not a substitute for reading the actual licenses or talking to a lawyer when stakes are high.
LicenseHound walks every transitive dependency in your repo, maps each to its SPDX license, and flags pairs like this one in PR comments. The CLI is free; the team dashboard is paid.